Applying neural network language models to weighted finite state transducers for automatic speech recognition

ABSTRACT

Systems and processes for converting speech-to-text are provided. In one example process, speech input can be received. A sequence of states and arcs of a weighted finite state transducer (WFST) can be traversed. A negating finite state transducer (FST) can be traversed. A virtual FST can be composed using a neural network language model and based on the sequence of states and arcs of the WFST. The one or more virtual states of the virtual FST can be traversed to determine a probability of a candidate word given one or more history candidate words. Text corresponding to the speech input can be determined based on the probability of the candidate word given the one or more history candidate words. An output can be provided based on the text corresponding to the speech input.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Ser. No. 62/262,286, filed on Dec. 2, 2015, entitled APPLYING NEURAL NETWORK LANGUAGE MODELS TO WEIGHTED FINITE STATE TRANSDUCERS FOR AUTOMATIC SPEECH RECOGNITION, which is hereby incorporated by reference in its entirety for all purposes. This application also relates to the following co-pending applications: U.S. Non-Provisional patent application Ser. No. 14/494,305, “METHOD FOR SUPPORTING DYNAMIC GRAMMARS IN WFST-BASED ASR,” filed Sep. 23, 2014, which is hereby incorporated by reference in its entirety for all purposes.

FIELD

The present disclosure relates generally to speech-to-text conversion, and more specifically to techniques for applying neural network language models to weighted finite state transducers for automatic speech recognition.

BACKGROUND

Language models can be implemented in automatic speech recognition (ASR) to predict the most probable current word (w) given one or more history words (h). Conventionally, statistical language models, such as n-gram language models, are applied in automatic speech recognition. Statistical language models are based on estimating conditional probabilities (e.g., probability of the current word given the one or more history words, P(w|h)) using training data, such as corpora of text. In order to achieve high recognition accuracy, the length of history words can be between two to four words (e.g., 3-gram to 5-gram). As the amount of language training data used in modern ASR systems is very large, the number of n-grams in n-gram language models can be very large. Large numbers of n-grams pose memory and speed problems in run-time ASR systems. Techniques such as pruning and cut-off have been implemented to control the actual number of n-grams in an n-gram language model. However, pruning and cut-off can reduce the accuracy of speech recognition.

BRIEF SUMMARY

Systems and processes for converting speech-to-text are provided. In one example process, speech input can be received. A sequence of states and arcs of a weighted finite state transducer (WFST) can be traversed based on the speech input. The sequence of states and arcs can represent one or more history candidate words and a current candidate word. A first probability of the candidate word given the one or more history candidate words can be determined by traversing the sequences of states and arcs of the WFST. A negating finite state transducer (FST) can be traversed, where traversing the negating FST can negate the first probability of the candidate word given the one or more history candidate words. A virtual FST can be composed using a neural network language model and based on the sequence of states and arcs of the WFST. One or more virtual states of the virtual FST can represent the current candidate word. The one or more virtual states of the virtual FST can be traversed, where a second probability of the candidate word given the one or more history candidate words is determined by traversing the one or more virtual states of the virtual FST. Text corresponding to the speech input can be determined based on the second probability of the candidate word given the one or more history candidate words. An output can be provided based on the text corresponding to the speech input.

BRIEF DESCRIPTION OF THE FIGURES

For a better understanding of the various described embodiments, reference should be made to the Description of Embodiments below, in conjunction with the following drawings in which like reference numerals refer to corresponding parts throughout the figures.

FIG. 1A is a block diagram illustrating a portable multifunction device with a touch-sensitive display in accordance with some examples.

FIG. 1B is a block diagram illustrating exemplary components for event handling in accordance with some embodiments.

FIG. 2 illustrates a portable multifunction device having a touch screen in accordance with some embodiments.

FIG. 3 is a block diagram of an exemplary multifunction device with a display and a touch-sensitive surface in accordance with some embodiments.

FIGS. 4A and 4B illustrate an exemplary user interface for a menu of applications on a portable multifunction device in accordance with some embodiments.

FIG. 5 illustrates an exemplary schematic block diagram of an automatic speech recognition module in accordance with some embodiments.

FIG. 6 illustrates an exemplary neural network language model in accordance with some embodiments.

FIGS. 7A-B illustrate flow diagrams of an exemplary process for speech-to-text conversion in accordance with some embodiments.

FIGS. 8A-C illustrate flow diagrams of an exemplary process for speech-to-text conversion in accordance with some embodiments.

FIG. 9 illustrates a functional block diagram of an electronic device in accordance with some embodiments.

DESCRIPTION OF EMBODIMENTS

In the following description of the disclosure and embodiments, reference is made to the accompanying drawings in which it is shown by way of illustration of specific embodiments that can be practiced. It is to be understood that other embodiments and examples can be practiced and changes can be made without departing from the scope of the disclosure.

Techniques for applying neural network language models to weighted finite state transducers for automatic speech recognition are described herein. Neural network language models (NNLMs) map word indices to a continuous space and word probability distributions are estimated as smooth functions in that space. As a result, compared to n-gram language models, NNLMs provide better generalization for n-grams that are not found or are infrequently found in the training data. This enables greater recognition accuracy when NNLMs are implemented in automatic speech recognition. However, because NNLMs are generally configured to model the unabridged n-gram (e.g., for feedforward NNLMs) or the entire word history (e.g., for recurrent NNLMs), it can be difficult to efficiently integrate NNLMs into single pass WFST speech recognition decoder systems. In particular, NNLMs implemented in automatic speech recognition can be computationally expensive.

One approach to improving computational efficiency can be to first convert the NNLM into an intermediate form, such as an n-gram representation or a prefix tree representation of word sequences. The intermediate form can then be pruned or optimized before being integrated into the single pass WFST. However, the conversion process can require applying approximations, which can reduce the overall accuracy of the speech recognition system. The benefits of the NNLM are thus not fully experienced using this approach. Another approach to improving computation efficiency can be to implement a two-pass strategy where an n-gram language model is utilized to guide the initial decoding in the WFST. The NNLM can then be utilized during a second pass only to resolve ambiguities. However, the two-pass strategy can result in increased latency, which can negatively impact user experience for real-time applications. Further, because the NNLM is only utilized to resolve ambiguities, the benefits associated with the NNLM are not realized for every speech recognition pass.

Systems and processes for applying neural network language models to weighted finite state transducers for automatic speech recognition are described below. The exemplary systems and processes described herein can efficiently integrate an NNLM in a single pass WFST without sacrificing accuracy. In particular, the NNLM can be directly integrated with the WFST without converting the NNLM into an intermediate form (e.g., an n-gram or prefix tree representation). Further, the NNLM can be utilized during every decoding pass, rather than only during the rescoring pass in the latency time.

Embodiments of electronic devices, systems for speech-to-text conversion on such devices, and associated processes for using such devices are described. In some embodiments, the device is a portable communications device, such as a mobile telephone, that also contains other functions, such as PDA and/or music player functions. Exemplary embodiments of portable multifunction devices include, without limitation, the iPhone®, iPod Touch®, and iPad® devices from Apple Inc. of Cupertino, Calif. Other portable devices, such as laptops or tablet computers with touch-sensitive surfaces (e.g., touch screen displays and/or touch pads), may also be used. Exemplary embodiments of laptop and tablet computers include, without limitation, the iPad® and MacBook® devices from Apple Inc. of Cupertino, Calif. It should also be understood that, in some embodiments, the device is not a portable communications device, but is a desktop computer. Exemplary embodiments of desktop computers include, without limitation, the Mac Pro® from Apple Inc. of Cupertino, Calif.

In the discussion that follows, an electronic device that includes a display and a touch-sensitive surface is described. It should be understood, however, that the electronic device optionally includes one or more other physical user-interface devices, such as button(s), a physical keyboard, a mouse, and/or a joystick.

The device may support a variety of applications, such as one or more of the following: a drawing application, a presentation application, a word processing application, a website creation application, a disk authoring application, a spreadsheet application, a gaming application, a telephone application, a video conferencing application, an e-mail application, an instant messaging application, a workout support application, a photo management application, a digital camera application, a digital video camera application, a web browsing application, a digital music player application, and/or a digital video player application.

The various applications that are executed on the device optionally use at least one common physical user-interface device, such as the touch-sensitive surface. One or more functions of the touch-sensitive surface as well as corresponding information displayed on the device are, optionally, adjusted and/or varied from one application to the next and/or within a respective application. In this way, a common physical architecture (such as the touch-sensitive surface) of the device optionally supports the variety of applications with user interfaces that are intuitive and transparent to the user.

FIGS. 1A and 1B are block diagrams illustrating exemplary portable multifunction device 100 with touch-sensitive displays 112 in accordance with some embodiments. Touch-sensitive display 112 is sometimes called a “touch screen” for convenience. Device 100 may include memory 102. Device 100 may include memory controller 122, one or more processing units (CPU's) 120, peripherals interface 118, RF circuitry 108, audio circuitry 110, speaker 111, microphone 113, input/output (I/O) subsystem 106, other input or control devices 116, and external port 124. Device 100 may include one or more optical sensors 164. Bus/signal lines 103 may allow these components to communicate with one another. Device 100 is one example of an electronic device that could be used to perform the techniques described herein. Specific implementations involving device 100 may have more or fewer components than shown, may combine two or more components, or may have a different configuration or arrangement of the components. The various components shown in FIGS. 1A and 1B may be implemented in hardware, software, or a combination of both. The components also can be implemented using one or more signal processing and/or application specific integrated circuits.

Memory 102 may include one or more computer readable storage mediums. The computer readable storage mediums may be tangible and non-transitory. Further, one or more computer readable storage mediums may include instructions for performing any of the methods or processes described herein. Memory 102 may include high-speed random access memory and may also include non-volatile memory, such as one or more magnetic disk storage devices, flash memory devices, or other non-volatile solid-state memory devices. Memory controller 122 may control access to memory 102 by other components of device 100.

Peripherals interface 118 can be used to couple input and output peripherals of the device to CPU 120 and memory 102. The one or more processors 120 run or execute various software programs and/or sets of instructions stored in memory 102 to perform various functions for device 100 and to process data. In some embodiments, peripherals interface 118, CPU 120, and memory controller 122 may be implemented on a single chip, such as chip 104. In some other embodiments, they may be implemented on separate chips.

RF (radio frequency) circuitry 108 receives and sends RF signals, also called electromagnetic signals. RF circuitry 108 converts electrical signals to/from electromagnetic signals and communicates with communications networks and other communications devices via the electromagnetic signals. RF circuitry 108 may include well-known circuitry for performing these functions, including but not limited to an antenna system, an RF transceiver, one or more amplifiers, a tuner, one or more oscillators, a digital signal processor, a CODEC chipset, a subscriber identity module (SIM) card, memory, and so forth. RF circuitry 108 may communicate with networks, such as the Internet, also referred to as the World Wide Web (WWW), an intranet and/or a wireless network, such as a cellular telephone network, a wireless local area network (LAN) and/or a metropolitan area network (MAN), and other devices by wireless communication. The wireless communication may use any of a plurality of communications standards, protocols and technologies, including but not limited to Global System for Mobile Communications (GSM), Enhanced Data GSM Environment (EDGE), high-speed downlink packet access (HSDPA), wideband code division multiple access (W-CDMA), code division multiple access (CDMA), time division multiple access (TDMA), Bluetooth, Bluetooth Low Energy (BTLE), Wireless Fidelity (Wi-Fi) (e.g., IEEE 502.11a, IEEE 502.11b, IEEE 802.11g and/or IEEE 802.11n), voice over Internet Protocol (VoIP), Wi-MAX, a protocol for e-mail (e.g., Internet message access protocol (IMAP) and/or post office protocol (POP)), instant messaging (e.g., extensible messaging and presence protocol (XMPP), Session Initiation Protocol for Instant Messaging and Presence Leveraging Extensions (SIMPLE), Instant Messaging and Presence Service (IMPS)), and/or Short Message Service (SMS), or any other suitable communication protocol, including communication protocols not yet developed as of the filing date of this document.

Audio circuitry 110, speaker 111, and microphone 113 provide an audio interface between a user and device 100. Audio circuitry 110 receives audio data from peripherals interface 118, converts the audio data to an electrical signal, and transmits the electrical signal to speaker 111. Speaker 111 converts the electrical signal to human-audible sound waves. Audio circuitry 110 also receives electrical signals converted by microphone 113 from sound waves. Audio circuitry 110 converts the electrical signal to audio data and transmits the audio data to peripherals interface 118 for processing. Audio data may be retrieved from and/or transmitted to memory 102 and/or RF circuitry 108 by peripherals interface 118. In some embodiments, audio circuitry 110 also includes a headset jack (e.g., 212, FIG. 2). The headset jack provides an interface between audio circuitry 110 and removable audio input/output peripherals, such as output-only headphones or a headset with both output (e.g., a headphone for one or both ears) and input (e.g., a microphone).

I/O subsystem 106 couples input/output peripherals on device 100, such as touch screen 112 and other input control devices 116, to peripherals interface 118. I/O subsystem 106 may include display controller 156 and one or more input controllers 160 for other input or control devices. The one or more input controllers 160 receive/send electrical signals from/to other input or control devices 116. The other input control devices 116 may include physical buttons (e.g., push buttons, rocker buttons, etc.), dials, slider switches, joysticks, click wheels, and so forth. In some alternate embodiments, input controller(s) 160 may be coupled to any (or none) of the following: a keyboard, infrared port, USB port, and a pointer device such as a mouse. The one or more buttons (e.g., 208, FIG. 2) may include an up/down button for volume control of speaker 111 and/or microphone 113. The one or more buttons may include a push button (e.g., 206, FIG. 2). A quick press of the push button may disengage a lock of touch screen 112 or begin a process that uses gestures on the touch screen to unlock the device, as described in U.S. patent application Ser. No. 11/322,549, “Unlocking a Device by Performing Gestures on an Unlock Image,” filed Dec. 23, 2005, U.S. Pat. No. 7,657,849, which is hereby incorporated by reference in its entirety. A longer press of the push button (e.g., 206) may turn power to device 100 on or off. The user may be able to customize a functionality of one or more of the buttons. Touch screen 112 is used to implement virtual or soft buttons and one or more soft keyboards.

Touch-sensitive display 112 provides an input interface and an output interface between the device and a user. Display controller 156 receives and/or sends electrical signals from/to touch screen 112. Touch screen 112 displays visual output to the user. The visual output may include graphics, text, icons, video, and any combination thereof (collectively termed “graphics”). In some embodiments, some or all of the visual output may correspond to user-interface objects.

Touch screen 112 has a touch-sensitive surface, sensor or set of sensors that accepts input from the user based on haptic and/or tactile contact. Touch screen 112 and display controller 156 (along with any associated modules and/or sets of instructions in memory 102) detect contact (and any movement or breaking of the contact) on touch screen 112 and converts the detected contact into interaction with user-interface objects (e.g., one or more soft keys, icons, web-pages or images) that are displayed on touch screen 112. In an exemplary embodiment, a point of contact between touch screen 112 and the user corresponds to a finger of the user.

Touch screen 112 may use LCD (liquid crystal display) technology, LPD (light emitting polymer display) technology, or LED (light emitting diode) technology, although other display technologies may be used in other embodiments. Touch screen 112 and display controller 156 may detect contact and any movement or breaking thereof using any of a plurality of touch sensing technologies now known or later developed, including but not limited to capacitive, resistive, infrared, and surface acoustic wave technologies, as well as other proximity sensor arrays or other elements for determining one or more points of contact with touch screen 112. In an exemplary embodiment, projected mutual capacitance sensing technology is used, such as that found in the iPhone® and iPod Touch® from Apple Inc. of Cupertino, Calif.

A touch-sensitive display in some embodiments of touch screen 112 may be analogous to the multi-touch sensitive touchpads described in the following U.S. Pat. No. 6,323,846 (Westerman et al.), U.S. Pat. No. 6,570,557 (Westerman et al.), and/or U.S. Pat. No. 6,677,932 (Westerman), and/or U.S. Patent Publication 2002/0015024A1, each of which is hereby incorporated by reference in its entirety. However, touch screen 112 displays visual output from device 100, whereas touch sensitive touchpads do not provide visual output.

A touch-sensitive display in some embodiments of touch screen 112 may be as described in the following applications: (1) U.S. patent application Ser. No. 11/381,313, “Multipoint Touch Surface Controller,” filed May 2, 2006; (2) U.S. patent application Ser. No. 10/840,862, “Multipoint Touchscreen,” filed May 6, 2004; (3) U.S. patent application Ser. No. 10/903,964, “Gestures For Touch Sensitive Input Devices,” filed Jul. 30, 2004; (4) U.S. patent application Ser. No. 11/048,264, “Gestures For Touch Sensitive Input Devices,” filed Jan. 31, 2005; (5) U.S. patent application Ser. No. 11/038,590, “Mode-Based Graphical User Interfaces For Touch Sensitive Input Devices,” filed Jan. 18, 2005; (6) U.S. patent application Ser. No. 11/228,758, “Virtual Input Device Placement On A Touch Screen User Interface,” filed Sep. 16, 2005; (7) U.S. patent application Ser. No. 11/228,700, “Operation Of A Computer With A Touch Screen Interface,” filed Sep. 16, 2005; (8) U.S. patent application Ser. No. 11/228,737, “Activating Virtual Keys Of A Touch-Screen Virtual Keyboard,” filed Sep. 16, 2005; and (9) U.S. patent application Ser. No. 11/367,749, “Multi-Functional Hand-Held Device,” filed Mar. 3, 2006. All of these applications are incorporated by reference herein in their entirety.

Touch screen 112 may have a video resolution in excess of 100 dpi. In some embodiments, the touch screen has a video resolution of approximately 160 dpi. The user may make contact with touch screen 112 using any suitable object or appendage, such as a stylus, a finger, and so forth. In some embodiments, the user interface is designed to work primarily with finger-based contacts and gestures, which can be less precise than stylus-based input due to the larger area of contact of a finger on the touch screen. In some embodiments, the device translates the rough finger-based input into a precise pointer/cursor position or command for performing the actions desired by the user.

In some embodiments, in addition to the touch screen, device 100 may include a touchpad (not shown) for activating or deactivating particular functions. In some embodiments, the touchpad is a touch-sensitive area of the device that, unlike the touch screen, does not display visual output. The touchpad may be a touch-sensitive surface that is separate from touch screen 112 or an extension of the touch-sensitive surface formed by the touch screen.

Device 100 also includes power system 162 for powering the various components. Power system 162 may include a power management system, one or more power sources (e.g., battery, alternating current (AC)), a recharging system, a power failure detection circuit, a power converter or inverter, a power status indicator (e.g., a light-emitting diode (LED)) and any other components associated with the generation, management and distribution of power in portable devices.

Device 100 may also include one or more optical sensors 164. FIGS. 1A and 1B show an optical sensor coupled to optical sensor controller 158 in I/O subsystem 106. Optical sensor 164 may include charge-coupled device (CCD) or complementary metal-oxide semiconductor (CMOS) phototransistors. Optical sensor 164 receives light from the environment, projected through one or more lens, and converts the light to data representing an image. In conjunction with imaging module 143 (also called a camera module), optical sensor 164 may capture still images or video. In some embodiments, an optical sensor is located on the back of device 100, opposite touch screen display 112 on the front of the device, so that the touch screen display may be used as a viewfinder for still and/or video image acquisition. In some embodiments, an optical sensor is located on the front of the device so that the user's image may be obtained for videoconferencing while the user views the other video conference participants on the touch screen display. In some embodiments, the position of optical sensor 164 can be changed by the user (e.g., by rotating the lens and the sensor in the device housing) so that a single optical sensor 164 may be used along with the touch screen display for both video conferencing and still and/or video image acquisition.

Device 100 may also include one or more proximity sensors 166. FIGS. 1A and 1B show proximity sensor 166 coupled to peripherals interface 118. Alternately, proximity sensor 166 may be coupled to input controller 160 in I/O subsystem 106. Proximity sensor 166 may perform as described in U.S. patent application Ser. No. 11/241,839, “Proximity Detector In Handheld Device”; Ser. No. 11/240,788, “Proximity Detector In Handheld Device”; Ser. No. 11/620,702, “Using Ambient Light Sensor To Augment Proximity Sensor Output”; Ser. No. 11/586,862, “Automated Response To And Sensing Of User Activity In Portable Devices”; and Ser. No. 11/638,251, “Methods And Systems For Automatic Configuration Of Peripherals,” which are hereby incorporated by reference in their entirety. In some embodiments, the proximity sensor turns off and disables touch screen 112 when the multifunction device is placed near the user's ear (e.g., when the user is making a phone call).

Device 100 optionally also includes one or more tactile output generators 167. FIG. 1A shows a tactile output generator coupled to haptic feedback controller 161 in I/O subsystem 106. Tactile output generator 167 optionally includes one or more electroacoustic devices such as speakers or other audio components and/or electromechanical devices that convert energy into linear motion such as a motor, solenoid, electroactive polymer, piezoelectric actuator, electrostatic actuator, or other tactile output generating component (e.g., a component that converts electrical signals into tactile outputs on the device). Contact intensity sensor 165 receives tactile feedback generation instructions from haptic feedback module 133 and generates tactile outputs on device 100 that are capable of being sensed by a user of device 100. In some embodiments, at least one tactile output generator is collocated with, or proximate to, a touch-sensitive surface (e.g., touch-sensitive display system 112) and, optionally, generates a tactile output by moving the touch-sensitive surface vertically (e.g., in/out of a surface of device 100) or laterally (e.g., back and forth in the same plane as a surface of device 100). In some embodiments, at least one tactile output generator sensor is located on the back of device 100, opposite touch screen display 112, which is located on the front of device 100.

Device 100 may also include one or more accelerometers 168. FIGS. 1A and 1B show accelerometer 168 coupled to peripherals interface 118. Alternately, accelerometer 168 may be coupled to an input controller 160 in I/O subsystem 106. Accelerometer 168 may perform as described in U.S. Patent Publication No. 20050190059, “Acceleration-based Theft Detection System for Portable Electronic Devices,” and U.S. Patent Publication No. 20060017692, “Methods And Apparatuses For Operating A Portable Device Based On An Accelerometer,” both of which are incorporated by reference herein in their entirety. In some embodiments, information is displayed on the touch screen display in a portrait view or a landscape view based on an analysis of data received from the one or more accelerometers. Device 100 optionally includes, in addition to accelerometer(s) 168, a magnetometer (not shown) and a GPS (or GLONASS or other global navigation system) receiver (not shown) for obtaining information concerning the location and orientation (e.g., portrait or landscape) of device 100.

In some embodiments, the software components stored in memory 102 include operating system 126, communication module (or set of instructions) 128, contact/motion module (or set of instructions) 130, graphics module (or set of instructions) 132, text input module (or set of instructions) 134, Global Positioning System (GPS) module (or set of instructions) 135, and applications (or sets of instructions) 136. Furthermore, in some embodiments memory 102 stores device/global internal state 157, as shown in FIGS. 1A, 1B and 3. Device/global internal state 157 includes one or more of: active application state, indicating which applications, if any, are currently active; display state, indicating what applications, views or other information occupy various regions of touch screen display 112; sensor state, including information obtained from the device's various sensors and input control devices 116; and location information concerning the device's location and/or attitude.

Operating system 126 (e.g., Darwin, RTXC, LINUX, UNIX, OS X, iOS, WINDOWS, or an embedded operating system such as VxWorks) includes various software components and/or drivers for controlling and managing general system tasks (e.g., memory management, storage device control, power management, etc.) and facilitates communication between various hardware and software components.

Communication module 128 facilitates communication with other devices over one or more external ports 124 and also includes various software components for handling data received by RF circuitry 108 and/or external port 124. External port 124 (e.g., Universal Serial Bus (USB), FIREWIRE, etc.) is adapted for coupling directly to other devices or indirectly over a network (e.g., the Internet, wireless LAN, etc.). In some embodiments, the external port is a multi-pin connector that is the same as, or similar to and/or compatible with the 5-pin and/or 30-pin connectors used on devices made by Apple Inc.

Contact/motion module 130 may detect contact with touch screen 112 (in conjunction with display controller 156) and other touch sensitive devices (e.g., a touchpad or physical click wheel). Contact/motion module 130 includes various software components for performing various operations related to detection of contact, such as determining if contact has occurred (e.g., detecting a finger-down event), determining if there is movement of the contact and tracking the movement across the touch-sensitive surface (e.g., detecting one or more finger-dragging events), and determining if the contact has ceased (e.g., detecting a finger-up event or a break in contact). Contact/motion module 130 receives contact data from the touch-sensitive surface. Determining movement of the point of contact, which is represented by a series of contact data, may include determining speed (magnitude), velocity (magnitude and direction), and/or an acceleration (a change in magnitude and/or direction) of the point of contact. These operations may be applied to single contacts (e.g., one finger contacts) or to multiple simultaneous contacts (e.g., “multitouch”/multiple finger contacts). In some embodiments, contact/motion module 130 and display controller 156 detects contact on a touchpad. In some embodiments, contact/motion module 130 and controller 160 detects contact on a click wheel.

Contact/motion module 130 may detect a gesture input by a user. Different gestures on the touch-sensitive surface have different contact patterns. Thus, a gesture may be detected by detecting a particular contact pattern. For example, detecting a finger tap gesture includes detecting a finger-down event followed by detecting a finger-up (lift off) event at the same position (or substantially the same position) as the finger-down event (e.g., at the position of an icon). As another example, detecting a finger swipe gesture on the touch-sensitive surface includes detecting a finger-down event followed by detecting one or more finger-dragging events, and subsequently followed by detecting a finger-up (lift off) event.

Graphics module 132 includes various known software components for rendering and displaying graphics on touch screen 112 or other display, including components for changing the intensity of graphics that are displayed. As used herein, the term “graphics” includes any object that can be displayed to a user, including without limitation text, web-pages, icons (such as user-interface objects including soft keys), digital images, videos, animations and the like. In some embodiments, graphics module 132 stores data representing graphics to be used. Each graphic may be assigned a corresponding code. Graphics module 132 receives, from applications etc., one or more codes specifying graphics to be displayed along with, if necessary, coordinate data and other graphic property data, and then generates screen image data to output to display controller 156.

Haptic feedback module 133 includes various software components for generating instructions used by tactile output generator(s) 167 to produce tactile outputs at one or more locations on device 100 in response to user interactions with device 100.

Text input module 134, which may be a component of graphics module 132, provides soft keyboards for entering text in various applications (e.g., contacts 137, e-mail 140, IM 141, browser 147, and any other application that needs text input).

GPS module 135 determines the location of the device and provides this information for use in various applications (e.g., to telephone 138 for use in location-based dialing, to camera 143 as picture/video metadata, and to applications that provide location-based services such as weather widgets, local yellow page widgets, and map/navigation widgets).

Applications 136 may include the following modules (or sets of instructions), or a subset or superset thereof:

-   -   Contacts module 137 (sometimes called an address book or contact         list);     -   Telephone module 138;     -   Video conferencing module 139;     -   E-mail client module 140;     -   Instant messaging (IM) module 141;     -   Workout support module 142;     -   Camera module 143 for still and/or video images;     -   Image management module 144;     -   Video player module;     -   Music player module;     -   Browser module 147;     -   Calendar module 148;     -   Widget modules 149, which may include one or more of: weather         widget 149-1, stocks widget 149-2, calculator widget 149-3,         alarm clock widget 149-4, dictionary widget 149-5, and other         widgets obtained by the user, as well as user-created widgets         149-6;     -   Widget creator module 150 for making user-created widgets 149-6;     -   Search module 151;     -   Video and music player module 152, which merges video player         module and music player module;     -   Notes module 153;     -   Map module 154; and/or     -   Online video module 155.

Examples of other applications 136 that may be stored in memory 102 include other word processing applications, other image editing applications, drawing applications, presentation applications, JAVA-enabled applications, encryption, digital rights management, voice recognition, and voice replication.

In conjunction with touch screen 112, display controller 156, contact/motion module 130, graphics module 132, and text input module 134, contacts module 137 may be used to manage an address book or contact list (e.g., stored in application internal state 192 of contacts module 137 in memory 102 or memory 370), including: adding name(s) to the address book; deleting name(s) from the address book; associating telephone number(s), e-mail address(es), physical address(es) or other information with a name; associating an image with a name; categorizing and sorting names; providing telephone numbers or e-mail addresses to initiate and/or facilitate communications by telephone 138, video conference module 139, e-mail 140, or IM 141; and so forth.

In conjunction with RF circuitry 108, audio circuitry 110, speaker 111, microphone 113, touch screen 112, display controller 156, contact/motion module 130, graphics module 132, and text input module 134, telephone module 138 may be used to enter a sequence of characters corresponding to a telephone number, access one or more telephone numbers in address book 137, modify a telephone number that has been entered, dial a respective telephone number, conduct a conversation and disconnect or hang up when the conversation is completed. As noted above, the wireless communication may use any of a plurality of communications standards, protocols and technologies.

In conjunction with RF circuitry 108, audio circuitry 110, speaker 111, microphone 113, touch screen 112, display controller 156, optical sensor 164, optical sensor controller 158, contact module 130, graphics module 132, text input module 134, contacts module 137, and telephone module 138, video conference module 139 includes executable instructions to initiate, conduct, and terminate a video conference between a user and one or more other participants in accordance with user instructions.

In conjunction with RF circuitry 108, touch screen 112, display controller 156, contact/motion module 130, graphics module 132, and text input module 134, e-mail client module 140 includes executable instructions to create, send, receive, and manage e-mail in response to user instructions. In conjunction with image management module 144, e-mail client module 140 makes it very easy to create and send e-mails with still or video images taken with camera module 143.

In conjunction with RF circuitry 108, touch screen 112, display controller 156, contact module 130, graphics module 132, and text input module 134, the instant messaging module 141 includes executable instructions to enter a sequence of characters corresponding to an instant message, to modify previously entered characters, to transmit a respective instant message (for example, using a Short Message Service (SMS) or Multimedia Message Service (MMS) protocol for telephony-based instant messages or using XMPP, SIMPLE, or IMPS for Internet-based instant messages), to receive instant messages and to view received instant messages. In some embodiments, transmitted and/or received instant messages may include graphics, photos, audio files, video files and/or other attachments as are supported in a MMS and/or an Enhanced Messaging Service (EMS). As used herein, “instant messaging” refers to both telephony-based messages (e.g., messages sent using SMS or MMS) and Internet-based messages (e.g., messages sent using XMPP, SIMPLE, or IMPS).

In conjunction with RF circuitry 108, touch screen 112, display controller 156, contact module 130, graphics module 132, text input module 134, GPS module 135, map module 154, and music player module, workout support module 142 includes executable instructions to create workouts (e.g., with time, distance, and/or calorie burning goals); communicate with workout sensors (sports devices); receive workout sensor data; calibrate sensors used to monitor a workout; select and play music for a workout; and display, store and transmit workout data.

In conjunction with touch screen 112, display controller 156, optical sensor(s) 164, optical sensor controller 158, contact/motion module 130, graphics module 132, and image management module 144, camera module 143 includes executable instructions to capture still images or video (including a video stream) and store them into memory 102, modify characteristics of a still image or video, or delete a still image or video from memory 102.

In conjunction with touch screen 112, display controller 156, contact/motion module 130, graphics module 132, text input module 134, and camera module 143, image management module 144 includes executable instructions to arrange, modify (e.g., edit), or otherwise manipulate, label, delete, present (e.g., in a digital slide show or album), and store still and/or video images.

In conjunction with touch screen 112, display controller 156, contact/motion module 130, graphics module 132, audio circuitry 110, and speaker 111, video player module 145 includes executable instructions to display, present or otherwise play back videos (e.g., on touch screen 112 or on an external, connected display via external port 124).

In conjunction with touch screen 112, display system controller 156, contact module 130, graphics module 132, audio circuitry 110, speaker 111, RF circuitry 108, and browser module 147, music player module 146 includes executable instructions that allow the user to download and play back recorded music and other sound files stored in one or more file formats, such as MP3 or AAC files. In some embodiments, device 100 may include the functionality of an MP3 player, such as an iPod (trademark of Apple Inc.).

In conjunction with RF circuitry 108, touch screen 112, display controller 156, contact/motion module 130, graphics module 132, and text input module 134, browser module 147 includes executable instructions to browse the Internet in accordance with user instructions, including searching, linking to, receiving, and displaying web-pages or portions thereof, as well as attachments and other files linked to web-pages.

In conjunction with RF circuitry 108, touch screen 112, display controller 156, contact/motion module 130, graphics module 132, text input module 134, e-mail client module 140, and browser module 147, calendar module 148 includes executable instructions to create, display, modify, and store calendars and data associated with calendars (e.g., calendar entries, to do lists, etc.) in accordance with user instructions.

In conjunction with RF circuitry 108, touch screen 112, display controller 156, contact/motion module 130, graphics module 132, text input module 134, and browser module 147, widget modules 149 are mini-applications that may be downloaded and used by a user (e.g., weather widget 149-1, stocks widget 149-2, calculator widget 149-3, alarm clock widget 149-4, and dictionary widget 149-5) or created by the user (e.g., user-created widget 149-6). In some embodiments, a widget includes an HTML (Hypertext Markup Language) file, a CSS (Cascading Style Sheets) file, and a JavaScript file. In some embodiments, a widget includes an XML (Extensible Markup Language) file and a JavaScript file (e.g., Yahoo! Widgets).

In conjunction with RF circuitry 108, touch screen 112, display controller 156, contact/motion module 130, graphics module 132, text input module 134, and browser module 147, the widget creator module 150 may be used by a user to create widgets (e.g., turning a user-specified portion of a web-page into a widget).

In conjunction with touch screen 112, display controller 156, contact/motion module 130, graphics module 132, and text input module 134, search module 151 includes executable instructions to search for text, music, sound, image, video, and/or other files in memory 102 that match one or more search criteria (e.g., one or more user-specified search terms) in accordance with user instructions.

In conjunction with touch screen 112, display controller 156, contact/motion module 130, graphics module 132, audio circuitry 110, speaker 111, RF circuitry 108, and browser module 147, video and music player module 152 includes executable instructions that allow the user to download and play back recorded music and other sound files stored in one or more file formats, such as MP3 or AAC files, and executable instructions to display, present, or otherwise play back videos (e.g., on touch screen 112 or on an external, connected display via external port 124). In some embodiments, device 100 optionally includes the functionality of an MP3 player, such as an iPod (trademark of Apple Inc.).

In conjunction with touch screen 112, display controller 156, contact/motion module 130, graphics module 132, and text input module 134, notes module 153 includes executable instructions to create and manage notes, to-do lists, and the like in accordance with user instructions.

In conjunction with RF circuitry 108, touch screen 112, display controller 156, contact/motion module 130, graphics module 132, text input module 134, GPS module 135, and browser module 147, map module 154 may be used to receive, display, modify, and store maps and data associated with maps (e.g., driving directions; data on stores and other points of interest at or near a particular location; and other location-based data) in accordance with user instructions.

In conjunction with touch screen 112, display controller 156, contact/motion module 130, graphics module 132, audio circuitry 110, speaker 111, RF circuitry 108, text input module 134, e-mail client module 140, and browser module 147, online video module 155 includes instructions that allow the user to access, browse, receive (e.g., by streaming and/or download), play back (e.g., on the touch screen or on an external, connected display via external port 124), send an e-mail with a link to a particular online video, and otherwise manage online videos in one or more file formats, such as H.264. In some embodiments, instant messaging module 141, rather than e-mail client module 140, is used to send a link to a particular online video. Additional description of the online video application can be found in U.S. Provisional Patent Application No. 60/936,562, “Portable Multifunction Device, Method, and Graphical User Interface for Playing Online Videos,” filed Jun. 20, 2007, and U.S. patent application Ser. No. 11/968,067, “Portable Multifunction Device, Method, and Graphical User Interface for Playing Online Videos,” filed Dec. 31, 2007, the contents of which are hereby incorporated by reference in their entirety.

Each of the above identified modules and applications corresponds to a set of executable instructions for performing one or more functions described above and the methods described in this application (e.g., the computer-implemented methods and other information processing methods described herein). These modules (e.g., sets of instructions) need not be implemented as separate software programs, procedures or modules, and thus various subsets of these modules may be combined or otherwise rearranged in various embodiments. For example, video player module may be combined with music player module into a single module (e.g., video and music player module 152, FIG. 1B). In some embodiments, memory 102 may store a subset of the modules and data structures identified above. Furthermore, memory 102 may store additional modules and data structures not described above.

In some embodiments, memory 102 (or memory 370 of FIG. 3) may store various user-specific data, such as, for example, user-specific vocabulary data, preference data, data from the user's electronic address book, user generated to-do lists, user generated shopping lists, or the like.

In some embodiments, device 100 is a device where operation of a predefined set of functions on the device is performed exclusively through a touch screen and/or a touchpad. By using a touch screen and/or a touchpad as the primary input control device for operation of device 100, the number of physical input control devices (such as push buttons, dials, and the like) on device 100 may be reduced.

The predefined set of functions that may be performed exclusively through a touch screen and/or a touchpad include navigation between user interfaces. In some embodiments, the touchpad, when touched by the user, navigates device 100 to a main, home, or root menu from any user interface that may be displayed on device 100. In such embodiments, a “menu button” is implemented using a touchpad. In some other embodiments, the menu button is a physical push button or other physical input control device instead of a touchpad.

FIG. 1B is a block diagram illustrating exemplary components for event handling in accordance with some embodiments. In some embodiments, memory 102 (in FIG. 1A) or 370 (FIG. 3) includes event sorter 170 (e.g., in operating system 126) and a respective application 136-1 (e.g., any of the aforementioned applications 137-151, 155, 380-390).

Event sorter 170 receives event information and determines the application 136-1 and application view 191 of application 136-1 to which to deliver the event information. Event sorter 170 includes event monitor 171 and event dispatcher module 174. In some embodiments, application 136-1 includes application internal state 192, which indicates the current application view(s) displayed on touch sensitive display 112 when the application is active or executing. In some embodiments, device/global internal state 157 is used by event sorter 170 to determine which application(s) is(are) currently active, and application internal state 192 is used by event sorter 170 to determine application views 191 to which to deliver event information.

In some embodiments, application internal state 192 includes additional information, such as one or more of: resume information to be used when application 136-1 resumes execution, user interface state information that indicates information being displayed or that is ready for display by application 136-1, a state queue for enabling the user to go back to a prior state or view of application 136-1, and a redo/undo queue of previous actions taken by the user.

Event monitor 171 receives event information from peripherals interface 118. Event information includes information about a sub-event (e.g., a user touch on touch-sensitive display 112, as part of a multi-touch gesture). Peripherals interface 118 transmits information it receives from I/O subsystem 106 or a sensor, such as proximity sensor 166, accelerometer(s) 168, and/or microphone 113 (through audio circuitry 110). Information that peripherals interface 118 receives from I/O subsystem 106 includes information from touch-sensitive display 112 or a touch-sensitive surface.

In some embodiments, event monitor 171 sends requests to the peripherals interface 118 at predetermined intervals. In response, peripherals interface 118 transmits event information. In other embodiments, peripherals interface 118 transmits event information only when there is a significant event (e.g., receiving an input above a predetermined noise threshold and/or for more than a predetermined duration). In some embodiments, event sorter 170 also includes a hit view determination module 172 and/or an active event recognizer determination module 173.

Hit view determination module 172 provides software procedures for determining where a sub-event has taken place within one or more views, when touch sensitive display 112 displays more than one view. Views are made up of controls and other elements that a user can see on the display.

Another aspect of the user interface associated with an application is a set of views, sometimes herein called application views or user interface windows, in which information is displayed and touch-based gestures occur. The application views (of a respective application) in which a touch is detected may correspond to programmatic levels within a programmatic or view hierarchy of the application. For example, the lowest level view in which a touch is detected may be called the hit view, and the set of events that are recognized as proper inputs may be determined based, at least in part, on the hit view of the initial touch that begins a touch-based gesture.

Hit view determination module 172 receives information related to sub-events of a touch-based gesture. When an application has multiple views organized in a hierarchy, hit view determination module 172 identifies a hit view as the lowest view in the hierarchy which should handle the sub-event. In most circumstances, the hit view is the lowest level view in which an initiating sub-event occurs (e.g., the first sub-event in the sequence of sub-events that form an event or potential event). Once the hit view is identified by the hit view determination module 172, the hit view typically receives all sub-events related to the same touch or input source for which it was identified as the hit view.

Active event recognizer determination module 173 determines which view or views within a view hierarchy should receive a particular sequence of sub-events. In some embodiments, active event recognizer determination module 173 determines that only the hit view should receive a particular sequence of sub-events. In other embodiments, active event recognizer determination module 173 determines that all views that include the physical location of a sub-event are actively involved views, and therefore determines that all actively involved views should receive a particular sequence of sub-events. In other embodiments, even if touch sub-events were entirely confined to the area associated with one particular view, views higher in the hierarchy would still remain as actively involved views.

Event dispatcher module 174 dispatches the event information to an event recognizer (e.g., event recognizer 180). In embodiments including active event recognizer determination module 173, event dispatcher module 174 delivers the event information to an event recognizer determined by active event recognizer determination module 173. In some embodiments, event dispatcher module 174 stores in an event queue the event information, which is retrieved by a respective event receiver 182.

In some embodiments, operating system 126 includes event sorter 170. Alternatively, application 136-1 includes event sorter 170. In yet other embodiments, event sorter 170 is a stand-alone module, or a part of another module stored in memory 102, such as contact/motion module 130.

In some embodiments, application 136-1 includes a plurality of event handlers 190 and one or more application views 191, each of which includes instructions for handling touch events that occur within a respective view of the application's user interface. Each application view 191 of the application 136-1 includes one or more event recognizers 180. Typically, a respective application view 191 includes a plurality of event recognizers 180. In other embodiments, one or more of event recognizers 180 are part of a separate module, such as a user interface kit (not shown) or a higher level object from which application 136-1 inherits methods and other properties. In some embodiments, a respective event handler 190 includes one or more of: data updater 176, object updater 177, GUI updater 178, and/or event data 179 received from event sorter 170. Event handler 190 may utilize or call data updater 176, object updater 177, or GUI updater 178 to update the application internal state 192. Alternatively, one or more of the application views 191 include one or more respective event handlers 190. Also, in some embodiments, one or more of data updater 176, object updater 177, and GUI updater 178 are included in a respective application view 191.

A respective event recognizer 180 receives event information (e.g., event data 179) from event sorter 170 and identifies an event from the event information. Event recognizer 180 includes event receiver 182 and event comparator 184. In some embodiments, event recognizer 180 also includes at least a subset of: metadata 183, and event delivery instructions 188 (which may include sub-event delivery instructions).

Event receiver 182 receives event information from event sorter 170. The event information includes information about a sub-event, for example, a touch or a touch movement. Depending on the sub-event, the event information also includes additional information, such as location of the sub-event. When the sub-event concerns motion of a touch the event information may also include speed and direction of the sub-event. In some embodiments, events include rotation of the device from one orientation to another (e.g., from a portrait orientation to a landscape orientation, or vice versa), and the event information includes corresponding information about the current orientation (also called device attitude) of the device.

Event comparator 184 compares the event information to predefined event or sub-event definitions and, based on the comparison, determines an event or sub-event, or determines or updates the state of an event or sub-event. In some embodiments, event comparator 184 includes event definitions 186. Event definitions 186 contain definitions of events (e.g., predefined sequences of sub-events), for example, event 1 (187-1), event 2 (187-2), and others. In some embodiments, sub-events in an event (187) include, for example, touch begin, touch end, touch movement, touch cancellation, and multiple touching. In one example, the definition for event 1 (187-1) is a double tap on a displayed object. The double tap, for example, comprises a first touch (touch begin) on the displayed object for a predetermined phase, a first liftoff (touch end) for a predetermined phase, a second touch (touch begin) on the displayed object for a predetermined phase, and a second liftoff (touch end) for a predetermined phase. In another example, the definition for event 2 (187-2) is a dragging on a displayed object. The dragging, for example, comprises a touch (or contact) on the displayed object for a predetermined phase, a movement of the touch across touch-sensitive display 112, and liftoff of the touch (touch end). In some embodiments, the event also includes information for one or more associated event handlers 190.

In some embodiments, event definitions 187 include a definition of an event for a respective user-interface object. In some embodiments, event comparator 184 performs a hit test to determine which user-interface object is associated with a sub-event. For example, in an application view in which three user-interface objects are displayed on touch-sensitive display 112, when a touch is detected on touch-sensitive display 112, event comparator 184 performs a hit test to determine which of the three user-interface objects is associated with the touch (sub-event). If each displayed object is associated with a respective event handler 190, the event comparator uses the result of the hit test to determine which event handler 190 should be activated. For example, event comparator 184 selects an event handler associated with the sub-event and the object triggering the hit test.

In some embodiments, the definition for a respective event (187) also includes delayed actions that delay delivery of the event information until after it has been determined whether the sequence of sub-events does or does not correspond to the event recognizer's event type.

When a respective event recognizer 180 determines that the series of sub-events do not match any of the events in event definitions 186, the respective event recognizer 180 enters an event impossible, event failed, or event ended state, after which it disregards subsequent sub-events of the touch-based gesture. In this situation, other event recognizers, if any, that remain active for the hit view continue to track and process sub-events of an ongoing touch-based gesture.

In some embodiments, a respective event recognizer 180 includes metadata 183 with configurable properties, flags, and/or lists that indicate how the event delivery system should perform sub-event delivery to actively involved event recognizers. In some embodiments, metadata 183 includes configurable properties, flags, and/or lists that indicate how event recognizers may interact, or are enabled to interact, with one another. In some embodiments, metadata 183 includes configurable properties, flags, and/or lists that indicate whether sub-events are delivered to varying levels in the view or programmatic hierarchy.

In some embodiments, a respective event recognizer 180 activates event handler 190 associated with an event when one or more particular sub-events of an event are recognized. In some embodiments, a respective event recognizer 180 delivers event information associated with the event to event handler 190. Activating an event handler 190 is distinct from sending (and deferred sending) sub-events to a respective hit view. In some embodiments, event recognizer 180 throws a flag associated with the recognized event, and event handler 190 associated with the flag catches the flag and performs a predefined process.

In some embodiments, event delivery instructions 188 include sub-event delivery instructions that deliver event information about a sub-event without activating an event handler. Instead, the sub-event delivery instructions deliver event information to event handlers associated with the series of sub-events or to actively involved views. Event handlers associated with the series of sub-events or with actively involved views receive the event information and perform a predetermined process.

In some embodiments, data updater 176 creates and updates data used in application 136-1. For example, data updater 176 updates the telephone number used in contacts module 137, or stores a video file used in video player module. In some embodiments, object updater 177 creates and updates objects used in application 136-1. For example, object updater 177 creates a new user-interface object or updates the position of a user-interface object. GUI updater 178 updates the GUI. For example, GUI updater 178 prepares display information and sends it to graphics module 132 for display on a touch-sensitive display.

In some embodiments, event handler(s) 190 includes or has access to data updater 176, object updater 177, and GUI updater 178. In some embodiments, data updater 176, object updater 177, and GUI updater 178 are included in a single module of a respective application 136-1 or application view 191. In other embodiments, they are included in two or more software modules.

It shall be understood that the foregoing discussion regarding event handling of user touches on touch-sensitive displays also applies to other forms of user inputs to operate multifunction devices 100 with input devices, not all of which are initiated on touch screens. For example, mouse movement and mouse button presses, optionally coordinated with single or multiple keyboard presses or holds; contact movements such as taps, drags, scrolls, etc. on touchpads; pen stylus inputs; movement of the device; oral instructions; detected eye movements; biometric inputs; and/or any combination thereof are optionally utilized as inputs corresponding to sub-events which define an event to be recognized.

FIG. 2 illustrates a portable multifunction device 100 having a touch screen 112 in accordance with some embodiments. The touch screen may display one or more graphics within user interface (UI) 200. In this embodiment, as well as others described below, a user may select one or more of the graphics by making contact or touching the graphics, for example, with one or more fingers 202 (not drawn to scale in the figure) or one or more styluses 203 (not drawn to scale in the figure). In some embodiments, selection of one or more graphics occurs when the user breaks contact with the one or more graphics. In some embodiments, the contact may include a gesture, such as one or more taps, one or more swipes (from left to right, right to left, upward and/or downward) and/or a rolling of a finger (from right to left, left to right, upward and/or downward) that has made contact with device 100. In some embodiments, inadvertent contact with a graphic may not select the graphic. For example, a swipe gesture that sweeps over an application icon may not select the corresponding application when the gesture corresponding to selection is a tap.

Device 100 may also include one or more physical buttons, such as “home” or menu button 204. As described previously, menu button 204 may be used to navigate to any application 136 in a set of applications that may be executed on device 100. Alternatively, in some embodiments, the menu button is implemented as a soft key in a GUI displayed on touch screen 112.

In one embodiment, device 100 includes touch screen 112, menu button 204, push button 206 for powering the device on/off and locking the device, volume adjustment button(s) 208, Subscriber Identity Module (SIM) card slot 210, head set jack 212, and docking/charging external port 124. Push button 206 may be used to turn the power on/off on the device by depressing the button and holding the button in the depressed state for a predefined time interval; to lock the device by depressing the button and releasing the button before the predefined time interval has elapsed; and/or to unlock the device or initiate an unlock process. In an alternative embodiment, device 100 also may accept verbal input for activation or deactivation of some functions through microphone 113.

FIG. 3 is a block diagram of an exemplary multifunction device with a display and a touch-sensitive surface in accordance with some embodiments. Device 300 need not be portable. In some embodiments, device 300 is a laptop computer, a desktop computer, a tablet computer, a multimedia player device, a navigation device, an educational device (such as a child's learning toy), a gaming system, or a control device (e.g., a home or industrial controller). Device 300 typically includes one or more processing units (CPU's) 310, one or more network or other communications interfaces 360, memory 370, and one or more communication buses 320 for interconnecting these components. Communication buses 320 may include circuitry (sometimes called a chipset) that interconnects and controls communications between system components. Device 300 includes input/output (I/O) interface 330 comprising display 340, which is typically a touch screen display. I/O interface 330 also may include a keyboard and/or mouse (or other pointing device) 350 and touchpad 355. Memory 370 includes high-speed random access memory, such as DRAM, SRAM, DDR RAM or other random access solid state memory devices; and may include non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid state storage devices. Memory 370 may optionally include one or more storage devices remotely located from CPU(s) 310. In some embodiments, memory 370 stores programs, modules, and data structures analogous to the programs, modules, and data structures stored in memory 102 of portable multifunction device 100 (FIG. 1), or a subset thereof. Furthermore, memory 370 may store additional programs, modules, and data structures not present in memory 102 of portable multifunction device 100. For example, memory 370 of device 300 may store drawing module 380, presentation module 382, word processing module 384, website creation module 386, disk authoring module 388, and/or spreadsheet module 390, while memory 102 of portable multifunction device 100 (FIG. 1) may not store these modules.

Each of the above identified elements in FIG. 3 may be stored in one or more of the previously mentioned memory devices. Each of the above identified modules corresponds to a set of instructions for performing a function described above. The above identified modules or programs (i.e., sets of instructions) need not be implemented as separate software programs, procedures or modules, and thus various subsets of these modules may be combined or otherwise re-arranged in various embodiments. In some embodiments, memory 370 may store a subset of the modules and data structures identified above. Furthermore, memory 370 may store additional modules and data structures not described above.

Attention is now directed towards embodiments of user interfaces (“UI”) that may be implemented on portable multifunction device 100. FIG. 4A illustrates exemplary user interfaces for a menu of applications on portable multifunction device 100 in accordance with some embodiments. Similar user interfaces may be implemented on device 300. In some embodiments, user interface 400 includes the following elements, or a subset or superset thereof:

-   -   Signal strength indicator(s) 402 for wireless communication(s),         such as cellular and Wi-Fi signals;     -   Time 404;     -   Bluetooth indicator 405;     -   Battery status indicator 406;     -   Tray 408 with icons for frequently used applications, such as:         -   Icon 416 for telephone module 138, labeled “Phone,” which             optionally includes an indicator 414 of the number of missed             calls or voicemail messages;         -   Icon 418 for e-mail client module 140, labeled “Mail,” which             optionally includes an indicator 410 of the number of unread             e-mails;         -   Icon 420 for browser module 147, labeled “Browser;” and         -   Icon 422 for video and music player module 152, also             referred to as iPod (trademark of Apple Inc.) module 152,             labeled “iPod;” and     -   Icons for other applications, such as:         -   Icon 424 for IM module 141, labeled “Messages;”         -   Icon 426 for calendar module 148, labeled “Calendar;”         -   Icon 428 for image management module 144, labeled “Photos;”         -   Icon 430 for camera module 143, labeled “Camera;”         -   Icon 432 for online video module 155, labeled “Online             Video;”         -   Icon 434 for stocks widget 149-2, labeled “Stocks;”         -   Icon 436 for map module 154, labeled “Maps;”         -   Icon 438 for weather widget 149-1, labeled “Weather;”         -   Icon 440 for alarm clock widget 149-4, labeled “Clock;”         -   Icon 442 for workout support module 142, labeled “Workout             Support;”         -   Icon 444 for notes module 153, labeled “Notes;” and         -   Icon 446 for a settings application or module, labeled             “Settings,” which provides access to settings for device 100             and its various applications 136.

FIG. 4B illustrates an exemplary user interface on a device (e.g., device 300, FIG. 3) with a touch-sensitive surface 451 (e.g., a tablet or touchpad 355, FIG. 3) that is separate from the display 450 (e.g., touch screen display 112). Although many of the examples which follow will be given with reference to inputs on touch screen display 112 (where the touch sensitive surface and the display are combined), in some embodiments, the device detects inputs on a touch-sensitive surface that is separate from the display, as shown in FIG. 4B. In some embodiments the touch sensitive surface (e.g., 451) has a primary axis (e.g., 452) that corresponds to a primary axis (e.g., 453) on the display (e.g., 450). In accordance with these embodiments, the device detects contacts (e.g., 460 and 462) with the touch-sensitive surface 451 at locations that correspond to respective locations on the display (e.g., 460 corresponds to 468 and 462 corresponds to 470). In this way, user inputs (e.g., contacts 460 and 462, and movements thereof) detected by the device on the touch-sensitive surface (e.g., 451) are used by the device to manipulate the user interface on the display (e.g., 450) of the multifunction device when the touch-sensitive surface is separate from the display. It should be understood that similar methods may be used for other user interfaces described herein.

Additionally, while the following examples are given primarily with reference to finger inputs (e.g., finger contacts, finger tap gestures, finger swipe gestures), it should be understood that, in some embodiments, one or more of the finger inputs are replaced with input from another input device (e.g., a mouse-based input or stylus input). For example, a swipe gesture is, optionally, replaced with a mouse click (e.g., instead of a contact) followed by movement of the cursor along the path of the swipe (e.g., instead of movement of the contact). As another example, a tap gesture is, optionally, replaced with a mouse click while the cursor is located over the location of the tap gesture (e.g., instead of detection of the contact followed by ceasing to detect the contact). Similarly, when multiple user inputs are simultaneously detected, it should be understood that multiple computer mice are, optionally, used simultaneously, or a mouse and finger contacts are, optionally, used simultaneously.

As used in the specification and claims, the term “open application” refers to a software application with retained state information (e.g., as part of device/global internal state 157 and/or application internal state 192). An open (e.g., executing) application is any one of the following types of applications:

-   -   an active application, which is currently displayed on display         112 (or a corresponding application view is currently displayed         on the display);     -   a background application (or background process), which is not         currently displayed on display 112, but one or more application         processes (e.g., instructions) for the corresponding application         are being processed by one or more processors 120 (i.e.,         running);     -   a suspended application, which is not currently running, and the         application is stored in a volatile memory (e.g., DRAM, SRAM,         DDR RAM, or other volatile random access solid state memory         device of memory 102); and     -   a hibernated application, which is not running, and the         application is stored in a non-volatile memory (e.g., one or         more magnetic disk storage devices, optical disk storage         devices, flash memory devices, or other non-volatile solid state         storage devices of memory 102).

As used herein, the term “closed application” refers to software applications without retained state information (e.g., state information for closed applications is not stored in a memory of the device). Accordingly, closing an application includes stopping and/or removing application processes for the application and removing state information for the application from the memory of the device. Generally, opening a second application while in a first application does not close the first application. When the second application is displayed and the first application ceases to be displayed, the first application becomes a background application.

FIG. 5 illustrates an exemplary schematic block diagram of ASR module 500 in accordance with some embodiments. In some embodiments, ASR module 500 can be implemented using one or more multifunction devices, including but not limited to devices 100, 400, and 900 (FIGS. 1A, 2, 4A-B, and 9). The multifunctional devices can include devices such as servers, personal computers, mobile device, or the like. In particular, ASR module 500 can be implemented in the memory (e.g., memory 102 or 370) and/or processor(s) (e.g., processor(s) 120 or 310) of one or more devices. ASR module 500 can enable speech recognition capabilities in a multifunctional device. In particular, ASR module 500 can be configured to perform any of the processes or methods described below (e.g., processes 700 and 800).

As shown in FIG. 5, ASR module 500 can include feature extractor 502 configured to process speech input and extract acoustic features from the speech input. In particular, feature extractor 502 can divide the speech input into a plurality of speech frames, each speech frame having a predetermined duration (e.g., 10 ms). Feature extractor 502 can further be configured to extract acoustic features (e.g., mel-frequency cepstral coefficients, etc.) from the plurality of audio frames. The acoustic features can be referred to as feature vectors. The acoustic features can represent various acoustic qualities of the speech input.

The extracted acoustic features can be received by recognition engine 504, which can utilize one or more FSTs and/or language models to convert the acoustic features into text. In particular, recognition engine 504 can use WFST 506, negating FST 508, n-gram language model 510, user-specific language model FST(s) 512, virtual FST interface 514, or NNLM 516 to convert the acoustic features into text.

WFST 506 can be a single optimized finite state transducer composed from various knowledge sources. In particular, WFST 506 can be composed from a Hidden Markov Model (HMM) topology, a context dependent phonetic model, a lexicon, and a language model. The combination of these knowledge sources can be optimized using conventional WFST optimization techniques, such as composition, determinization, or minimization. Decoding with WFST 506 using recognition engine 504 can thus be very efficient as a result of this optimization. In some examples, WFST 506 can be denoted as: HCLG _(s)=opt(H∘C∘L∘G _(s)) where H is an HMM topology transducer, C is a context dependent phonetic model transducer, L is a lexicon transducer, G_(s) is a language model transducer, and ∘ denotes the composition operation. The optimization operator opt( ) can perform, for example, epsilon-removal, weight pushing, composition, determinization, and minimization. In some examples, G_(s) can be an n-gram language model. In particular, G_(s) can be a limited sized n-gram language model in order for HCLG_(s) to be a compact and statistically optimized transducer. In some examples, G_(s) can be a unigram or a bigram language model.

In some examples, WFST 506 can be configured to model a non-terminal class as a candidate word. As described in greater detail below, a non-terminal class can be a class of words (e.g., an entity class such as names of persons, places, applications, media, etc.). In some examples, the non-terminal class can be derived from user-specific data (e.g., names in a user's contact list). WFST 506 can be configured to model any number of non-terminal classes.

Negating FST 508 can have the same structure and topology as the language model transducer G_(s) from which WFST 506 is built, except that the scores (e.g., costs, likelihoods, or probabilities) are negated. Negating FST 508 can be denoted as G_(s) ⁻¹. Negating FST 508 can be structured such that composing negating FST 508 with WFST 506 (HCLG_(s)) would negate the scores associated with the language model transducer G_(s). For example, if the weights of G_(s) are log probabilities, the weights of G_(s) are subtracted from HCLG_(s) when composing negating FST 508 with WFST 506. Recognition engine 504 can be configured to compose the negating FST 508 with WFST 506.

N-gram language model FST 510 can be a large vocabulary language model. In particular, n-gram language model FST 510 can have a greater number of n-grams than the language model G_(s) used to generate WFST 506. N-gram language model FST 510 can be used by recognition engine 504 to supplement WFST 506, thereby obtaining more accurate recognition results.

User-specific language model FST(s) 512 can include one or more language model FSTs that are generated using user-specific data. In particular, ASR module includes language model generator for generating user-specific language model FST(s) 512 using user-specific data. Language model generator 513 can be configured to receive or obtain user-specific data (e.g., block 802, described below), such as user input, user usage data, user profile information, or the like. Language model generator 513 can further be configured to generate one or more user-specific language model FSTs 512 using the user-specific data (e.g., block 804, described below). The one or more user-specific language model FSTs 512 can thus contain vocabulary and word sequences that are associated with a specific user of the electronic device. Each user-specific language model FST 512 can represent a particular non-terminal class. A non-terminal class can be a class of words. Examples of non-terminal classes can include names in a user's contact list ($ContactList) on the electronic device, names of applications ($AppList) in a user's electronic device, or names of places ($Place”) entered by a user on the electronic device.

Virtual FST interface 514 can be an interface for on-the-fly construction of one or more virtual FST using NNLM 516 and n-gram language model FST 510. In particular, virtual FST interface 514 can encode the sequence of states and arcs traversed in WFST 506 by recognition engine 504. Based on the sequence of states and arcs, virtual FST interface 514 can be configured to provide one or more history candidate words (h) to NNLM 516 or n-gram language model 510 and obtain a probability of a current candidate word given the one or more history candidate words (P(w|h)). Virtual FST interface 514 can thus enable NNLM 516 and/or n-gram language model FST 510 to be integrated with WFST 506 during run-time speech recognition.

NNLM 516 can be a multiple layer perceptron. FIG. 6 illustrates exemplary neural NNLM 600 that can be similar or identical to NNLM 516. NNLM 600 can include input layer 602, output layer 604, and one or more hidden layers 606 disposed between input layer 602 and output layer 604. In this example, NNLM 600 includes three hidden layers 606. It should be recognized, however, that in other examples, NNLM 600 can include any number of hidden layers 606.

Each layer of NNLM 600 can include multiple units. The units can be the basic computational elements of NNLM 600 and can be referred to as dimensions, neurons, or nodes. As shown in FIG. 6, input layer 602 can include input units 608, hidden layers 606 can include hidden units 610, and output layer 604 can include output units 612. Hidden layers 806 can each include any number of hidden units 810. The units can be interconnected by connections 614. Specifically, connections 614 can connect the units of one layer to the units of a subsequent layer. Further, each connection 614 can be associated with a weighting value and a bias followed by a nonlinear activation function. For simplicity, the weighting values and biases are not shown in FIG. 6.

Input layer 602 can represent a vocabulary table that maps one or more history candidate words (h) in a continuous space where each word is represented as a floating point vector. Input layer 602 can be configured to receive as inputs one or more history candidate words (h). In the present example, the one or more history candidate words include a first history word (w₁) and a second history word (w₂). Output layer 604 can be configured to estimate a probability distribution over the word to predict. In the present example, output layer 604 can be configured to output the probability of a third word (w₃) given the first history word (w₁) and the second history word (w₂). The number of output units 612 in output layer 604 can have the same number of neurons as the vocabulary size of NNLM 600. Thus, output layer 604 can be configured to output a plurality of probabilities of numerous candidate words given the word history. It should be recognized that NNLM 600 can be a feedforward NNLM or a recurrent NNLM.

With reference back to FIG. 5, recognition engine 504 can function as a decoder. In particular, recognition engine 504 can perform decoding functions such as composing, interpolating, or traversing functions described below in processes 700 and 800. For example, recognition engine 504 can traverse or compose one or more of WFST 506, negating FST 508, n-gram language model 510, and user-specific language model FST(s) 512 to obtain speech recognition results. Further, recognition engine 504 can compose one or more virtual FSTs using one or more of WFST 506, negating FST 508, n-gram language model 510, user-specific language model FST(s) 512, virtual FST interface 514, and NNLM 516. Recognition engine 504 can then traverse the one or more virtual FSTs to obtain the probability of a current candidate word given one or more history candidate words (P(w|h)).

FIGS. 7A-B and 8A-C illustrate flow diagrams of exemplary processes 700 and 800 for speech-to-text conversion in accordance with some embodiments. More specifically, processes 700 and 800 can apply a neural network language model to weighted finite state transducers for speech-to-text conversion. Processes 700 or 800 can be performed at one or more of devices 100, 300, and 900 (FIGS. 1A, 2, 3A-B, and 9), described herein. In particular, processes 700 or 800 can be performed using an ASR module (e.g., ASR module 500 of FIG. 5) implemented on one or more devices. It should be appreciated that some blocks in processes 700 or 800 can be combined, the order of some blocks can be changed, and some blocks can be omitted.

At block 702, speech input can be received. The speech input can be received via a microphone (e.g., microphone 113) of an electronic device. The speech input can be in the form of an acoustic signal or an audio file. The speech input can include a user utterance, such as a voice command, dictation, request, authentication phrase, or the like. In some examples, the speech input can be pre-processed using a feature extractor (e.g., feature extractor 502) where the speech input is divided into a plurality of speech frames (e.g., 10 ms speech frames) and acoustic features (e.g., mel-frequency cepstral coefficients, etc.) are extracted from the plurality of segments. The acoustic features are thus a representation of the speech input.

At block 704, a sequence of states and arcs of a WFST can be traversed based on the speech input (e.g., using the acoustic features of block 702). The WFST can be similar or identical to WFST 502 described above in FIG. 5. As described above, the WFST can be referred to as HCLG_(s). In particular, the WFST can be a single optimized finite state transducer composed from a Hidden Markov Model (HMM) topology (H), a context dependent phonetic model (C), a lexicon (L), and a language model (G_(s)). In some examples, the language model (G_(s)) from which the WFST is built can be a unigram language model or a bigram language model. The WFST can be a static finite state transducer built prior to receiving the speech input.

The sequence of states and arcs can represent one or more history candidate words (h) and a current candidate word (w). In some instances, the one or more history candidate words (h) can be referred to as context. In one example, the one or more history candidate words (h) can be “Let's go” and the current candidate word (w) can be “home.” By traversing the sequences of states and arcs of the WFST, a first probability of the candidate word given the one or more history candidate words (P₁(w|h)) can be determined.

At block 706, a negating FST can be composed with the WFST. The negating FST can be similar or identical to negating FST 508 described above. In particular, the negating FST can be a static FST built prior to receiving the speech input at block 702. The negating FST can have the same structure as the language model transducer G_(s) from which the WFST is built, except the scores (e.g., costs, likelihoods, or probabilities) are negated. Composing the negating FST can be represented as follows: HCLG _(s) ∘G _(s) ⁻¹ where HCLG_(s) denotes the WFST of block 704, G_(s) ⁻¹ denotes the negating FST, and ∘ denotes the composition operation. In some examples, block 706 can be performed prior to block 708. Further, in some examples, block 706 can be performed after block 704.

At block 708, the negating FST (G_(s) ⁻¹) can be traversed. More specifically, the negating FST composed with the WFST can be traversed. The negating FST can be traversed after traversing the sequence of states and arcs of the WFST at block 704. Traversing the negating FST can negate the first probability of the candidate word given the one or more history candidate words, P₁(w|h). The negating FST can be a static finite state transducer built prior to receiving the speech input at block 702.

At block 710, a second probability of the candidate word given the one or more history candidate words (P₂(w|h)) can be determined using a neural network language model (NNLM). The NNLM can be similar or identical to NNLMs 516 or 600, described above. In some examples, the NNLM can be a feedforward NNLM. In other examples, the NNLM can be a recurrent NNLM. The NNLM can be more accurate than the language model (G_(s)) used to build the WFST of block 704. In particular, the NNLM can be more accurate than the language model (G_(s)) in determining the probability of a word given a history of words. Further, in some examples, the NNLM can be more accurate than a higher order (e.g., 4-gram or greater) n-gram language model.

The second probability of the candidate word given the one or more history candidate words, P₂(w|h) can be determined using a virtual FST interface (e.g., virtual FST interface 514, described above). The virtual FST interface can encode the one or more history candidate words (h) and the current candidate word (w) traversed in the WFST. The one or more history candidate words (h) can be inputted into the NNLM (e.g., at input layer 602) using the virtual FST interface. Based on the input, the NNLM can output the probabilities of numerous candidate words given the one or more history candidate words (e.g., from output layer 604). The second probability of the current candidate word given the one or more history candidate words (P₂(w|h)) can be obtained from among the outputted probabilities of numerous candidate words given the one or more history candidate words.

At block 712, a virtual FST (e.g., virtual FST interface 514) can be composed using the NNLM of block 710 and based on the sequence of states and arcs of the WFST of block 704. In particular, the virtual FST can be composed using the second probability of the candidate word given the one or more history candidate words (P₂(w|h)) determined at block 710. The virtual FST can be a virtual representation of the NNLM. In particular, the virtual FST can encode the one or more history candidate words (h) traversed in the WFST at block 704. Further, the virtual FST can include one or more virtual states that represent the current candidate word with respect to the one or more history candidate words. Composing the virtual FST can be represented as follows: HCLG _(s) ∘G _(s) ⁻¹ ∘G ₁ _(_) _(NNLM) where G₁ _(_) _(NNLM) denotes the virtual FST. In some examples, the virtual FST can be deterministic where there is only one arc transitioning out of each of the one or more virtual states of the virtual FST. Further, the virtual FST can be composed on-the-fly, where the virtual FST is composed only after the sequence of states and arcs of the WFST are traversed. In particular, the virtual FST may not include states representing every candidate word outputting by the NNLM. Rather, the virtual FST can include virtual states representing only the current candidate words obtained from traversing the WFST at block 704. The WFST thus guides the decoding. As a result, the computational and memory requirements can be reduced, which in turn reduces latency and improves user experience. Block 710 can be performed prior to block 712.

At block 714, the one or more virtual states of the virtual FST can be traversed. The one or more virtual states of the virtual FST can encode a third probability of the candidate word given the one or more history candidate words (P₃(w|h)). The third probability of the candidate word given the one or more history candidate words (P₃(w|h)) can be determined based on the second probability of the candidate word given the one or more history candidate words (P₂(w|h)). For example, the third probability of the candidate word given the one or more history candidate words (P₂(w|h)) can be logarithmic representation of the second probability of the candidate word given the one or more history candidate words (P₂(w|h)). By traversing the one or more virtual states of the virtual FST, the third probability of the candidate word given the one or more history candidate words (P₃(w|h)) can be determined.

It should be appreciated that the virtual FST is composed and traversed for every speech recognition pass. Thus, the NNLM is utilized for every speech recognition pass and not merely implemented only for resolving ambiguities from the WFST. Further, it should be recognized that the NNLM is not initially converted into an intermediate form such as an n-gram representation or a prefix tree representation. Rather, the virtual FST is composed directly using the NNLM via the virtual FST interface. This preserves the accuracy advantages associated with the NNLM. At the same time, as described above, not all candidate word results from the NNLM are used to compose the virtual FST. Rather, the virtual FST can include virtual states representing only the current candidate words obtained from traversing the WFST at block 704. Thus, process 700 enables the greater accuracy of the NNLM to be leveraged in speech recognition while limiting the computational requirements by utilizing the candidate word results from the WFST to guide the composition of the virtual FST.

At block 716, text corresponding to the speech input can be determined based on the third probability of the candidate word given the one or more history candidate words (P₃(w|h)). In particular, the one or more history candidate words (h) and the candidate word (w) can represent one candidate speech recognition result among a plurality of candidate speech recognition results. For example, the one or more history candidate words (h) and the candidate word (w) can represent the candidate speech recognition result “Let's go home.” The candidate speech result “Let's go home” can be associated with a probability based on the third probability of the candidate word given the one or more history candidate words (P₃(w|h)). Other candidate speech recognition results can include “Let's go to Rome,” “Let's grow hope,” or the like. Each candidate speech recognition result can be associated with a probability. The plurality of candidate speech recognition results can be ranked according to their respective probabilities. The text corresponding to the speech input can be the candidate speech recognition result with the highest probability.

At block 718, an output can be provided based on the text corresponding to the speech input. For example, if the text corresponding to the speech input is determined at block 716 to be “Let's go home,” the text can be displayed on the electronic device implementing process 700. In another example, the speech input can be provided as a command to a digital assistant implemented on the electronic device. Based on the text “Let's go home,” the digital assistant can determine that the user wishes to obtain directions back home. In this example, the output can include map instructions on how to get home. It should be recognized that various other types of output can be provided based on the text corresponding to the speech input.

In some examples, the text can be determined using one or more additional language models. In these examples, blocks 712 and 714 can be repeated using one or more additional language models. For example, blocks 720-724 of FIG. 7B illustrate additional operations of process 700 that can be performed when the text corresponding to the speech input is determined using one or more additional language models. Blocks 720-724 can be performed prior to blocks 716 and 718.

At block 720, a second virtual FST can be composed using a second language model and based on the sequence of states and arcs. Block 720 can be similar to block 712 except that the second language model is different from the NNLM. For example, the second language models can be a large vocabulary n-gram language model or a second NNLM that is different from the NNLM of block 710. The second virtual FST can encode the one or more history candidate words. Further, the second virtual FST can include one or more virtual states that represent the current candidate word.

In some examples, the second virtual FST can be deterministic where there is only one arc transitioning out of each of the one or more virtual states of the second virtual FST. Further, the virtual FST can be composed on-the-fly. In particular, the virtual FST can include virtual states representing only the current candidate words obtained from traversing the WFST at block 704.

At block 722, the one or more virtual states of the second virtual FST can be traversed. The one or more virtual states of the virtual FST can encode a fourth probability of the candidate word given the one or more history candidate words (P₄(w|h)). The fourth probability of the candidate word given the one or more history candidate words can be derived using the second language model. By traversing the one or more virtual states of the second virtual FST, the fourth probability given the one or more history candidate words (P₄(w|h)) can be determined.

At block 724, the second probability of the candidate word given the one or more history candidate words (P₂(w|h)) and the fourth probability of the candidate word given the one or more history candidate words (P₄(w|h)) can be interpolated. The interpolation can be represented as follows: G ₁ _(_) _(combined) ←G ₁ _(_) _(NNLM)∘₊ G ₁ _(_) ₂ where G₁ _(_) _(NNLM) denotes the virtual FST, G₁ _(_) ₂ denotes the second virtual FST, and ∘₊ denotes the interpolation operation. A combined probability of the candidate word given the one or more history candidate words can be determined from the interpolation.

The text corresponding to the speech input at block 714 can be determined based on the combined probability of the candidate word given the one or more history candidate words. The text can thus be determined based on both the second probability of the candidate word given the one or more history candidate words (P₂(w|h)) and the fourth probability of the candidate word given the one or more history candidate words (P₄(w|h)). By determining the text using two language models, the accuracy of the speech recognition is improved. It should be recognized that any number of language models can be utilized for speech recognition using the above described framework. For example, the interpolation of block 724 can be performed using any number of probabilities determined from any number of language models as follows: G ₁ ←G ₁ _(_) _(NNLM)∘₊ G ₁ _(_) ₂ . . . ∘_(+ . . .) G ₁ _(_) _((n-1))∘₊ G ₁ _(_) _(n) where n is an integer and G₁ _(_) _(n) is the n^(th) virtual FST composed using the n^(th) language model.

With reference to FIGS. 8A-8C, process 800 depicts another exemplary process for speech-to-text conversion. Process 800 can be similar to process 700 except that the current candidate word can be modeled as a non-terminal class in the WFST.

At block 802, user-specific data can be received. The user-specific data can be obtained from the memory (e.g., memory 102 or 370) of the electronic device 102. In some examples, the user-specific data can be associated with a particular user profile on the electronic device. The user-specific data can include lists of words or word sequences associated with the user. In particular, the lists of words or word sequences can include entities associated with the user. The user-specific data can further include interaction frequencies associated with the words or word sequences.

In some examples, the user-specific usage data can include names found in a user's phonebook or contact list. In particular, input containing the contact information (e.g., names, numbers, addresses, etc.) can be received from the user in a variety of circumstances, such as in voice commands, voice dictation, emails, calls, messages, or the like. In some instances, the user's contact list can include names that may not be within the vocabulary of the automatic speech recognition system (e.g., ASR module 500). These out-of-vocabulary names can thus be received and used to provide recognition support for such user-specific words.

In some examples, the user-specific data can include names of applications on the electronic device (e.g., applications 136 on device 100). The names of the applications can be retrieved from the memory of the electronic device. Additionally, the names of the applications can be received from the user. For example, input containing the application names can be received from the user in a variety of circumstances, such as in voice commands to launch an application, close an application, direct instructions to an application, or the like. A user may also input application names when dictating emails, messages, or the like (e.g., recommending an application to a friend, posting to a social media feed the achievement of a new high score in a gaming application, or the like). In some instances, an application on a user device can have a name that may not be within the vocabulary of the automatic speech recognition system. The user-specific data can thus include a list of user applications to provide speech recognition support for such user-specific application names.

In some examples, the user-specific data can include names of media on the electronic device, media accessible to a user, or media otherwise associated with a user (e.g., media stored in memory on user device 102, media available via streaming applications, media available via the Internet, media available from cloud storage, media available from a subscription service, etc.). Media names can include song tracks, music album titles, playlist names, genre names, mix names, artist names, radio station names, channel names, video titles, performer names, podcast titles, podcast producer names, or the like. For example, input containing media names can be received from the user in a variety of circumstances, such as in voice commands to play a song, play a video, tune to a radio station, play a mix of a particular genre of music, play an album, play an artist's music, or the like. A user may also input media names when dictating messages, searching for media, or the like (e.g., recommending an album to a friend, searching for a new song to buy, searching for a video clip to play, etc.). In some instances, media on a user device or available from other sources can have names that may not be within the vocabulary of the automatic speech recognition system. A list of media associated with a particular user can thus be received and used, as discussed in further detail below, to provide recognition support for such user specific media names.

In some examples, the user-specific data can include information regarding the frequency of interaction with the various entities. For example, the frequency of interaction can reflect the number of times a contact name, application name, or media name is received or selected as input on the electronic device. The frequency of interaction can include a ranking of entities with which the user interacts the most. Further, favorite lists, speed dial lists, or the like can be used to reflect a likely frequency of interaction between the user and various contacts. It should be understood that the frequency of interaction can be represented in any of a variety of ways (e.g., probabilities, percentages, rankings, interaction counts, number of interactions over a particular time period, etc.).

It should be appreciated that user-specific data can include a variety of other entities associated with a user that can be useful for ensuring speech recognition accuracy. For example, the user-specific data can include the names of locations, restaurants, or favorite foods associated with the user. Likewise, a variety of context information or other user-specific details can be received for speech recognition purposes. In some examples, such other entities and context information can be accompanied by interaction frequency data similar to that discussed above reflecting, for example, the likelihood that a particular entity will correspond to a user's similar-sounding utterance. Block 802 can be performed prior to receiving the speech input at block 806.

At block 804, a user-specific language model FST can be generated using the user-specific data. The user-specific language model FST can be a non-terminal language model FST that corresponds to a non-terminal class. In particular, the user-specific language model FST can be configured to determine the probability of one or more candidate words with respect to all possible candidate word sequences for the non-terminal class. The non-terminal class can correspond to any class of words. In some examples, the non-terminal class can correspond to a particular entity type such as, contact names, application names, media names, places, or the like. In one example, the user-specific data can include contact names from the user's contact list in the electronic device. In particular, the user-specific data can include the frequency of occurrence of a contact name in user input with respect to all contact names in the contact list. In this example, a user-specific language model FST representing the non-terminal class “$ContactList” can be generated using the user-specific data. The user-specific language model FST can thus be configured to determine the probability of a particular contact name with respect to all contact names in the user's contact list. The user-specific language model FST can be a static FST and can be generated at block 804 prior to receiving the speech input at block 806.

At block 806, speech input can be received. Block 806 can be similar or identical to block 702, described above.

At block 808, a sequence of states and arcs of a WFST can be traversed based on the speech input. Block 808 can be similar to block 704, except that the current candidate word is modeled as a non-terminal class. The sequence of states and arcs can thus represent one or more history candidate words (h) and a non-terminal class (NT). In some examples, the non-terminal class represented by the sequence of states and arcs can be the non-terminal class corresponding to the user-specific language model FST generated at block 804. By traversing the sequences of states and arcs of the WFST, a first probability of the non-terminal class given the one or more history candidate words (P₁(NT|h)) can be determined. The non-terminal class can be a class type that represents a set of words or word sequences. One example of a non-terminal class can be “$FirstName,” which can include a set of words or word sequences corresponding to the names in the user's contact lists (e.g., Jon, Adam, Mary, Fred, Bob, Mary Jane, etc.). Another example of a non-terminal class can be “$Country,” which can include a set of words or word sequences corresponding to different countries (e.g., United States, Mexico, France, Germany, China, Korea, Japan, etc.). In some examples, the non-terminal class can be based on the user-specific data of block 802. For example, the non-terminal class can be “$ContactList,” which can include the names in the user's contact list.

At block 810, a negating finite state transducer (FST) can be composed with the WFST. Block 810 can be similar or identical to block 706. In particular, the negating FST can be similar or identical to negating FST 508, described above. The negating FST can be a static FST built prior to receiving the speech input at block 806. The negating FST can have the same structure as the language model transducer G_(s) from which the WFST is built, except the scores (e.g., costs, likelihoods, or probabilities) are negated.

At block 812, a negating FST can be traversed. Block 812 can be similar or identical to block 708. In particular, traversing the negating FST can negate the first probability of the non-terminal class given the one or more history candidate words (P₁(NT|h)). The negating FST can be a static finite state transducer built prior to receiving the speech input at block 806.

At block 814, a second probability of the non-terminal class given the one or more history candidate words (P₂(NT|h)) can be determined using an NNLM. Block 814 can be similar to block 710, described above. In particular, the NNLM can be similar or identical to NNLMs 516 or 600, described above. In some examples, the NNLM can be a feedforward NNLM. In other examples, the NNLM can be a recurrent NNLM. The NNLM can be more accurate than the language model (G_(s)) used to build the WFST of block 808. In some examples, the NNLM can be more accurate than a higher order (e.g., 4-gram or greater) n-gram language model.

At block 816, a user-specific language model FST (G_(NT)) corresponding to the non-terminal class can be traversed. The user-specific language model FST (G_(NT)) can be a non-terminal language model FST. For example, the user-specific language model FST (G_(NT)) generated at block 804 can be traversed. By traversing the user-specific language model FST (G_(NT)), a probability of a current candidate word among a plurality of candidate words represented in the user-specific language model FST can be determined. Each of the plurality of candidate words represented in the user-specific language model FST can be associated with a non-terminal class.

At block 818, a virtual FST (G₁) can be composed using the NNLM of block 814 and the user-specific language model FST (G_(NT)) of block 816, and be based on the sequence of states and arcs of the WFST at block 808. In particular, the virtual FST (G₁) can be composed by composing a virtual NNLM FST (G₁ _(_) _(NNLM)) with the user-specific language model FST (G_(NT)) as follows: G ₁ ←G ₁ _(_) _(NNLM)∘_(·) G _(NT) where ∘_(·) denotes the composition operation with respect to a non-terminal class. The virtual NNLM FST (G₁ _(_) _(NNLM)) can be a virtual representation of the NNLM and can be composed on-the fly in a similar manner as described in block 712. In particular, the virtual NNLM FST (G₁ _(_) _(NNLM)) can be composed using the second probability of the non-terminal class given the one or more history candidate words (P₂(NT|h)) determined at block 814. The virtual NNLM FST (G₁ _(_) _(NNLM)) can encode the one or more history candidate words (h) traversed in the WFST at block 808. Further, the virtual NNLM FST (G₁ _(_) _(NNLM)) can include one or more virtual states that represent the non-terminal class (NT) with respect to the one or more history candidate words (h).

One or more virtual states of the virtual FST (G₁) can represent a current candidate word (w) corresponding to the non-terminal class (NT). For example, if the non-terminal class represents names in the user's contact list, the one or more virtual states of the virtual FST (G₁) can represent a current candidate word (w), such as “Bob,” “Joe,” or “Mike,” corresponding to a name in the user's contact list. The one or more virtual states of the virtual FST can be composed using phone-words from the WFST and based on the current candidate word (w) represented in the user-specific language model FST (G_(NT)). Phone-words can be words that represent phones. For example, if the current candidate word represented in the user-specific language model FST is “Mike” with a pronunciation of “M-AI-K,” it can be represented by phone-words “M”, “AI”, and “K.” The WFST can be modified to generate these phone-words and the one or more virtual states of the virtual FST can be composed using these phone-words. Further, the virtual FST can be composed using the probability of the current candidate word (w) among the plurality of candidate words represented in the user-specific language model FST (block 816). The virtual FST (G₁) can be deterministic where only one arc transitions out of each virtual state of the one or more virtual states of the virtual FST.

It should be appreciated that in some examples, more than one user-specific language model FST can be implemented. In particular, each user-specific language model FST can represent a different non-terminal class. In these examples, the virtual FST (G₁) can be composed with the user-specific language model FSTs as follows: G ₁ ←G ₁ _(_) _(NNLM)∘_(·)(G _(NT1) , . . . G _(NTn)) where n is an integer, and G_(NT1), . . . , G_(NTn) denotes n different user-specific language model FSTs.

At block 820, the one or more virtual states of the virtual FST can be traversed. The one or more virtual states of the virtual FST can encode the probability of the candidate word given the one or more history words and the non-terminal class (P(w|h,NT). The probability of the candidate word given the one or more history words and the non-terminal class (P(w|h,NT) can be based on the second probability of the non-terminal class given the one or more history candidate words (P₂(NT|h) and the probability of the current candidate word (w) among the plurality of candidate words represented in the user-specific language model FST (block 816). By traversing the virtual state of the virtual FST, a probability of the current candidate word given the one or more history candidate words and the non-terminal class (P₁(w|h,NT)) can be determined.

It should be recognized that in some examples, the one or more virtual states can represent two or more current candidate words corresponding to the non-terminal class. For example, the non-terminal class “$ContactList” can include names having more than one word (e.g., “Mary Jane,” “Bob Jones,” “Joe Black,” or “Mike Jordon Smith”). In these examples, the probability of two or more current candidate words given the one or more history candidate words and the non-terminal class (P₁ (w|h,NT)) can be determined.

At block 822, text corresponding to the speech input can be determined based on the probability of the current candidate word given the one or more history candidate words and the non-terminal class (P₁(w|h,NT)). Block 822 can be similar to block 716, described above.

At block 824, an output based on the text corresponding to the speech input can be provided. Block 824 can be similar or identical to block 718, described above.

It should be recognized that, in some examples, the text can be determined using one or more additional language models. In these examples, blocks 818 and 820 can be repeated using one or more additional language models. For example, blocks 826-830 of FIG. 8C illustrate additional operations of process 800 that can be performed when the text corresponding to the speech input is determined using one or more additional language models. Blocks 826-830 can be performed prior to blocks 822 and 824.

At block 826, a second virtual FST can be composed using a second language model and the user-specific language model FST and be based on the sequence of states and arcs of the WFST. Block 826 can be similar to block 818, except that a different language model is used. One or more virtual states of the second virtual FST can represent the current candidate word (w) corresponding to the non-terminal class (NT). In some examples, the second language model can be a second NNLM that is different from the NNLM of block 814. In these examples, the second virtual FST (G₁ _(_) ₂) can be composed by composing a virtual NNLM FST (G₁ _(_) _(NNLM2)) with the user-specific language model FST (G_(NT)) as follows: G ₁ _(_) ₂ ←G ₁ _(_) _(NNLM2)∘_(·) G _(NT) where ∘_(·) denotes the composition operation with respect to a non-terminal class. In other examples, the second language model can be a large vocabulary n-gram language model. In particular, the second language model can be a higher order (e.g., 4-gram or greater) n-gram language model. In these examples, the second virtual FST (G₁ _(_) ₂) can be composed by composing a virtual n-gram FST (G_(n-gram)) with the user-specific language model FST (G_(NT)) as follows: G ₁ _(_) ₂ ←G ₁ _(_) _(n-gram) replace G _(NT) where “replace” denotes the replace FST operation with respect to an n-gram language model FST (G₁ _(_) _(n-gram)).

At block 828, the one or more virtual states of the second virtual FST can be traversed. Block 828 can be similar to block 820, described above. In particular, the one or more virtual states can represent a current candidate word (w) with respect to the one or more history candidate words (h) and the non-terminal state (NT). The current candidate word (w) can be obtained from the user-specific language model FST. The one or more virtual states can encode the second probability of the current candidate word given the one or more history candidate words and the non-terminal class (P₂(w|h,NT)). By traversing the one or more virtual states of the second virtual FST, the second probability of the current candidate word given the one or more history candidate words and the non-terminal class (P₂(w|h,NT)) can be determined.

At block 830, the probability of the current candidate word given the one or more history candidate words and the non-terminal class (P₁(w|h,NT)) from block 820 and the second probability of the current candidate word given the one or more history candidate words and the non-terminal class (P₂(w|h,NT)) from block 828 can be interpolated. The interpolation can be represented as follows: G ₁ _(_) _(combined) ←G ₁ _(_) _(NNLM)∘₊ G ₁ _(_) ₂ where G₁ _(_) _(NNLM) denotes the virtual FST, G₁ _(_) ₂ denotes the second virtual FST, and ∘₊ denotes the interpolation operation. A combined probability of the candidate word given the one or more history candidate words can be determined from the interpolation.

The text corresponding to the speech input at block 822 can be determined based on the combined probability of the candidate word given the one or more history candidate words and the non-terminal class. The text is thus determined based on both the probability of the candidate word given the one or more history candidate words and the non-terminal class (P₁(w|h, NT)) and the second probability of the candidate word given the one or more history candidate words and the non-terminal class (P₂(w|h, NT)). By determining the text using two language models, the accuracy of the speech recognition is improved. As described above, it should be recognized that any number of language models can be utilized for speech recognition using the above described framework. The combined probability can thus be based on any number of language models.

In accordance with some embodiments, FIG. 9 shows a functional block diagram of an electronic device 900 configured in accordance with the principles of the various described embodiments, including those described with reference to FIG. 6. The functional blocks of the device are, optionally, implemented by hardware, software, or a combination of hardware and software to carry out the principles of the various described embodiments. It is understood by persons of skill in the art that the functional blocks described in FIG. 9 are, optionally, combined or separated into sub-blocks to implement the principles of the various described embodiments. Therefore, the description herein optionally supports any possible combination or separation or further definition of the functional blocks described herein.

As shown in FIG. 9, electronic device 900 can include display unit 902 configured to display text or user interface objects, and audio receiving unit 904 configured to receive speech input, and input unit 906 configured to receive user-specific data. Electronic device 900 can further include processing unit 908 coupled to display unit 902 and audio receiving unit 904. In some examples, processing unit 908 can include traversing unit 910, composing unit 912, determining unit 914, providing unit 916, interpolating unit 918, receiving unit 920, and determining unit 916.

In accordance with some embodiments, processing unit 908 is configured to traverse (e.g., with traversing unit 910), based on the speech input, a sequence of states and arcs of a weighted finite state transducer (WFST). The sequence of states and arcs represents one or more history candidate words and a current candidate word. A first probability of the candidate word given the one or more history candidate words is determined by traversing the sequences of states and arcs of the WFST. Processing unit 908 is further configured to traverse (e.g., with traversing unit 910) a negating finite state transducer (FST). Traversing the negating FST negates the first probability of the candidate word given the one or more history candidate words. Processing unit 908 is further configured to compose (e.g., with composing unit 912) a virtual FST using a neural network language model and based on the sequence of states and arcs of the WFST, where one or more virtual states of the virtual FST represent the current candidate word. Processing unit 908 is further configured to traverse (e.g., with traversing unit 910) the one or more virtual states of the virtual FST. A second probability of the candidate word given the one or more history candidate words is determined by traversing the one or more virtual states of the virtual FST. Processing unit 908 is further configured to determine (e.g., with determining unit 914), based on the second probability of the candidate word given the one or more history candidate words, text corresponding to the speech input. Processing unit 908 is further configured to provide (e.g., with providing unit 916) an output based on the text corresponding to the speech input.

In some examples, the virtual FST is composed after traversing the sequence of states and arcs of the WFST.

In some examples, only one arc transitions out of each virtual state of the one or more virtual states of the virtual FST.

In some examples, processing unit 908 is further configured to determine (e.g., with determining unit 914), using the neural network language model, a third probability of the candidate word given the one or more history candidate words. The virtual FST is composed using the third probability of the candidate word given the one or more history candidate words.

In some examples, processing unit 908 is further configured to compose (e.g., with composing unit 912) a second virtual FST using a second language model and based on the sequence of states and arcs, where one or more virtual states of the second virtual FST represents the current candidate word. Processing unit 908 is further configured to traverse (e.g., with traversing unit 910) the one or more virtual states of the second virtual FST, where a fourth probability of the candidate word given the one or more history candidate words is determined by traversing the one or more virtual states of the second virtual FST, and where the text corresponding to the speech input is determined based on the fourth probability of the candidate word given the one or more history candidate words.

In some examples, processing unit 908 is further configured to interpolate (e.g., with interpolating unit 918) the second probability of the candidate word given the one or more history candidate words and the fourth probability of the candidate word given the one or more history candidate words. A combined probability of the candidate word given the one or more history candidate words is determined by the interpolating. The text corresponding to the speech input is determined based on the combined probability of the candidate word given the one or more history candidate words.

In some examples, the second language model is an n-gram language model.

In some examples, processing unit 908 is further configured to compose (e.g., with composing unit 912) the negating FST with the WFST prior to traversing the negating FST.

In some examples, the virtual FST is composed prior to traversing the one or more virtual states of the virtual FST.

In some examples, the WFST is a static finite state transducer built prior to receiving the speech input. In some examples, the negating FST is a static finite state transducer built prior to receiving the speech input. In some examples, the WFST is a single finite state transducer composed from a Hidden Markov Model (HMM) topology, a context dependent phonetic model, a lexicon, and a language model. In some examples, the language model is a unigram language model or a bigram language model. In some examples, the neural network language model is more accurate than the language model. In some examples, the neural network language model is a feedforward neural network language model. In some examples, the neural network language model is a recurrent neural network language model.

In accordance with some embodiments, processing unit 908 is configured to traverse (e.g., with traversing unit 901), based on the speech input, a sequence of states and arcs of a weighted finite state transducer (WFST). The sequence of states and arcs represents one or more history candidate words and a non-terminal class and a first probability of the non-terminal class given the one or more history candidate words is determined by traversing the sequences of states and arcs of the WFST. Processing unit 908 is further configured to traverse (e.g., with traversing unit 910) a negating finite state transducer (FST), where traversing the negating FST negates the first probability of the non-terminal class given the one or more history candidate words. Processing unit 908 is further configured to compose (e.g., with composing unit 912) a virtual FST using a neural network language model and a user-specific language model FST, and based on the sequence of states and arcs of the WFST. One or more virtual states of the virtual FST represent a current candidate word corresponding to the non-terminal class. Processing unit 908 is further configured to traverse (e.g., with traversing 910) the one or more virtual states of the virtual FST, where a probability of the current candidate word given the one or more history candidate words and the non-terminal class is determined by traversing the one or more virtual states of the virtual FST. Processing unit 908 is further configured to determine (e.g., with determining unit 914), based on the probability of the current candidate word given the one or more history candidate words and the non-terminal class, text corresponding to the speech input. Processing unit 908 is further configured to provide (e.g., with providing unit 916) an output based on the text corresponding to the speech input.

In some examples, processing unit 908 is further configured to determine (e.g., with determining unit 914), using the neural network language model, a second probability of the non-terminal class given the one or more history candidate words. The virtual FST is composed using the second probability of the non-terminal class given the one or more history candidate words.

In some examples, processing unit 908 is further configured to traverse (e.g., with traversing unit 910) the user-specific language model FST, where a probability of the current candidate word among a plurality of candidate words represented in the user-specific language model FST is determined by traversing the user-specific language model FST. The virtual FST is composed using the probability of the current candidate word among the plurality of candidate words represented in the user-specific language model FST.

In some examples, the one or more virtual states of the virtual FST are composed using phone-word units from the WFST and based on the current candidate word represented in the user-specific language model FST.

In some examples, processing unit 908 is further configured to, prior to receiving the speech input, receive (e.g., with receiving unit 920 and via input unit 906) user-specific data and generate (e.g., with generating unit 922) the user-specific language model FST using the user-specific data.

In some examples, only one arc transitions out of each virtual state of the one or more virtual states of the virtual FST.

In some examples, processing unit 908 is further configured to compose (e.g., with composing unit 912) a second virtual FST using a second language model and the user-specific language model FST, and based on the sequence of states and arcs of the WFST, where one or more virtual states of the second virtual FST represent the current candidate word corresponding to the non-terminal class. Processing unit 908 is further configured to traverse (e.g., with traversing unit 910) the one or more virtual states of the second virtual FST, where a second probability of the current candidate word given the one or more history candidate words and the non-terminal class is determined by traversing the one or more virtual states of the second virtual FST. The text corresponding to the speech input is determined based on the second probability of the current candidate word given the one or more history candidate words and the non-terminal class.

In some examples, the second language model is an n-gram language model. In some examples, the second language model is a second neural network language model.

In some examples, processing unit 908 is further configured to interpolate (e.g., with interpolating unit 918) 1) the probability of the current candidate word given the one or more history candidate words and the non-terminal class and 2) the second probability of the current candidate word given the one or more history candidate words and the non-terminal class. A combined probability of the current candidate word given the one or more history candidate words and the non-terminal class is obtained by the interpolating. The text corresponding to the speech input is determined based on the combined probability of the current candidate word given the one or more history candidate words and the non-terminal class.

In some examples, the virtual FST is composed after traversing the sequence of states and arcs of the WFST.

In some examples, processing unit 908 is further configured to compose (e.g., with composing unit 912) the negating FST with the WFST prior to traversing the negating FST.

In some examples, the WFST is a static finite state transducer built prior to receiving the speech input. In some examples, the negating FST is a static finite state transducer built prior to receiving the speech input. In some examples, the WFST is a single finite state transducer composed from a Hidden Markov Model (HMM) topology, a context dependent phonetic model, a lexicon, and a language model. In some examples, the language model is a unigram language model or a bigram language model. In some examples, the neural network language model is more accurate than the language model. In some examples, the neural network language model is a feedforward neural network language model. In some examples, the neural network language model is a recurrent neural network language model.

The operation described above with respect to FIGS. 7A-B and 8A-C are, optionally, implemented by components depicted in FIGS. 1A-B, 3, 5, and 9. For example, receiving operations (702, 806) can be implemented by microphone 113, audio circuitry 110, and/or processor(s) 120. Traversing operations (704, 708, 714, 722, 808, 812, 816, 820), composing operations (706, 712, 720, 810, 818, 826), determining operations (710, 716, 814, 822), interpolating operations (724, 830), receiving operation (802), and generating operation 804 can be implemented by automatic speech recognition module 500. It would be clear to a person of ordinary skill in the art how other processes can be implemented based on the components depicted in FIGS. 1A-B, 3, 5, and 9.

It is understood by persons of skill in the art that the functional blocks described in FIG. 9 are, optionally, combined or separated into sub-blocks to implement the principles of the various described embodiments. Therefore, the description herein optionally supports any possible combination or separation or further definition of the functional blocks described herein. For example, processing unit 908 can have an associated “controller” unit that is operatively coupled with processing unit 908 to enable operation. This controller unit is not separately illustrated in FIG. 9 but is understood to be within the grasp of one of ordinary skill in the art who is designing a device having a processing unit 908, such as device 900. As another example, one or more units, such as audio receiving unit 904, may be hardware units outside of processing unit 908 in some embodiments. The description herein thus optionally supports combination, separation, and/or further definition of the functional blocks described herein.

In accordance with some implementations, a computer-readable storage medium (e.g., a non-transitory computer readable storage medium) is provided, the computer-readable storage medium storing one or more programs for execution by one or more processors of an electronic device, the one or more programs including instructions for performing any of the methods or processes described herein.

In accordance with some implementations, an electronic device (e.g., a portable electronic device) is provided that comprises means for performing any of the methods or processes described herein.

In accordance with some implementations, an electronic device (e.g., a portable electronic device) is provided that comprises a processing unit configured to perform any of the methods or processes described herein.

In accordance with some implementations, an electronic device (e.g., a portable electronic device) is provided that comprises one or more processors and memory storing one or more programs for execution by the one or more processors, the one or more programs including instructions for performing any of the methods or processes described herein.

Although the above description uses terms first, second, etc. to describe various elements, these elements should not be limited by the terms. These terms are only used to distinguish one element from another. For example, a first probability could be termed a second probability, and, similarly, a second probability could be termed a first probability, without departing from the scope of the present invention. The first probability and the second probability are both probabilities, but they are not the same probability.

The terminology used in the description of the various described embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various described embodiments and the appended claims, the singular forms “a”, “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “includes,” “including,” “comprises,” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The term “if” may be construed to mean “when” or “upon” or “in response to determining” or “in response to detecting,” depending on the context. Similarly, the phrase “if it is determined” or “if [a stated condition or event] is detected” may be construed to mean “upon determining” or “in response to determining” or “in accordance with determining” or “upon detecting [the stated condition or event]” or “in response to detecting [the stated condition or event],” depending on the context.

As described above, one aspect of the present technology is the gathering and use of data available from various sources to generate language models and thus improve the accuracy of speech recognition. The present disclosure contemplates that in some instances, this gathered data may include personal information data that uniquely identifies or can be used to contact or locate a specific person. Such personal information data can include demographic data, location-based data, telephone numbers, email addresses, home addresses, or any other identifying information.

The present disclosure recognizes that the use of such personal information data, in the present technology, can be used to the benefit of users. For example, the personal information data can be used to generate user-specific language models. Accordingly, use of such personal information data enables more accurate speech recognition. Further, other uses for personal information data that benefit the user are also contemplated by the present disclosure.

The present disclosure further contemplates that the entities responsible for the collection, analysis, disclosure, transfer, storage, or other use of such personal information data will comply with well-established privacy policies and/or privacy practices. In particular, such entities should implement and consistently use privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining personal information data private and secure. For example, personal information from users should be collected for legitimate and reasonable uses of the entity and not shared or sold outside of those legitimate uses. Further, such collection should occur only after receiving the informed consent of the users. Additionally, such entities would take any needed steps for safeguarding and securing access to such personal information data and ensuring that others with access to the personal information data adhere to their privacy policies and procedures. Further, such entities can subject themselves to evaluation by third parties to certify their adherence to widely accepted privacy policies and practices.

Despite the foregoing, the present disclosure also contemplates embodiments in which users selectively block the use of, or access to, personal information data. That is, the present disclosure contemplates that hardware and/or software elements can be provided to prevent or block access to such personal information data. For example, in the case of advertisement delivery services, the present technology can be configured to allow users to select to “opt in” or “opt out” of participation in the collection of personal information data during registration for services. In another example, users can select not to provide location information for targeted content delivery services. In yet another example, users can select to not provide precise location information, but permit the transfer of location zone information.

Therefore, although the present disclosure broadly covers use of personal information data to implement one or more various disclosed embodiments, the present disclosure also contemplates that the various embodiments can also be implemented without the need for accessing such personal information data. That is, the various embodiments of the present technology are not rendered inoperable due to the lack of all or a portion of such personal information data. For example, content can be selected and delivered to users by inferring preferences based on non-personal information data or a bare minimum amount of personal information, such as the content being requested by the device associated with a user, other non-personal information available to the content delivery services, or publically available information.

Although the disclosure and examples have been fully described with reference to the accompanying figures, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of the disclosure and examples as defined by the appended claims. 

What is claimed is:
 1. A non-transitory computer-readable medium having instructions stored thereon, the instructions, when executed by one or more processors, cause the one or more processors to: receive speech input; traverse, based on the speech input, a sequence of states and arcs of a weighted finite state transducer (WFST), wherein: the sequence of states and arcs represents one or more history candidate words and a current candidate word; and a first probability of the candidate word given the one or more history candidate words is determined by traversing the sequence of states and arcs of the WFST; traverse a negating finite state transducer (FST), wherein traversing the negating FST negates the first probability of the candidate word given the one or more history candidate words; compose a virtual FST using a neural network language model and based on the sequence of states and arcs of the WFST, wherein one or more virtual states of the virtual FST represent the current candidate word; traverse the one or more virtual states of the virtual FST, wherein a second probability of the candidate word given the one or more history candidate words is determined by traversing the one or more virtual states of the virtual FST; determine, based on the second probability of the candidate word given the one or more history candidate words, text corresponding to the speech input; based on the determined text, perform one or more tasks to obtain a result; and cause the result to be presented in spoken or visual form.
 2. The non-transitory computer-readable medium of claim 1, wherein the virtual FST is composed after traversing the sequence of states and arcs of the WFST.
 3. The non-transitory computer-readable medium of claim 1, wherein only one are transitions out of each virtual state of the one or more virtual states of the virtual FST.
 4. The non-transitory computer-readable medium of claim 1, wherein the instructions further cause the one or more processors to: determine, using the neural network language model, a third probability of the candidate word given the one or more history candidate words, wherein the virtual FST is composed using the third probability of the candidate word given the one or more history candidate words.
 5. The non-transitory computer-readable medium of claim 1, wherein the instructions further cause the one or more processors to: compose a second virtual FST using a second language model and based on the sequence of states and arcs, wherein one or more virtual states of the second virtual FST represents the current candidate word; and traverse the one or more virtual states of the second virtual FST, wherein a fourth probability of the candidate word given the one or more history candidate words is determined by traversing the one or more virtual states of the second virtual FST, and wherein the text corresponding to the speech input is determined based on the fourth probability of the candidate word given the one or more history candidate words.
 6. The non-transitory computer-readable medium of claim 5, wherein the instructions further cause the one or more processors to: interpolate the second probability of the candidate word given the one or more history candidate words and the fourth probability of the candidate word given the one or more history candidate words, and wherein: a combined probability of the candidate word given the one or more history candidate words is determined by the interpolating; and the text corresponding to the speech input is determined based on the combined probability of the candidate word given the one or more history candidate words.
 7. The non-transitory computer-readable medium of claim 5, wherein the second language model is an n-gram language model.
 8. The non-transitory computer-readable medium of claim 1, wherein the instructions further cause the one or more processors to: compose the negating FST with the WFST prior to traversing the negating FST.
 9. The non-transitory computer-readable medium of claim 8, wherein the virtual FST is composed prior to traversing the one or more virtual states of the virtual FST.
 10. The non-transitory computer-readable medium of claim 1, wherein the WFST is a static finite state transducer built prior to receiving the speech input.
 11. The non-transitory computer-readable medium of claim 1, wherein the negating FST is a static finite state transducer built prior to receiving the speech input.
 12. The non-transitory computer-readable medium of claim 1, wherein the WFST is a single finite state transducer composed from a Hidden Markov Model (HMM) topology, a context dependent phonetic model, a lexicon, and a language model.
 13. The non-transitory computer-readable medium of claim 12, wherein the language model is a unigram language model or a bigram language model.
 14. A non-transitory computer-readable medium having instructions stored thereon, the instructions, when executed by one or more processors, cause the one or more processors to: receive speech input; traverse, based on the speech input, a sequence of states and arcs of a weighted finite state transducer (WFST), wherein: the sequence of states and arcs represents one or more history candidate words and a non-terminal class; and a first probability of the non-terminal class given the one or more history candidate words is determined by traversing the sequence of states and arcs of the WFST; traverse a negating finite state transducer (FST), wherein traversing the negating FST negates the first probability of the non-terminal class given the one or more history candidate words; compose a virtual FST using a neural network language model and a user-specific language model FST, and based on the sequence of states and arcs of the WFST, wherein one or more virtual states of the virtual FST represent a current candidate word corresponding to the non-terminal class; traverse the one or more virtual states of the virtual FST, wherein a probability of the current candidate word given the one or more history candidate words and the non-terminal class is determined by traversing the one or more virtual states of the virtual FST; determine, based on the probability of the current candidate word given the one or more history candidate words and the non-terminal class, text corresponding to the speech input; based on the determined text, perform one or more tasks to obtain a result; and cause the result to be presented in spoken or visual form.
 15. The non-transitory computer-readable medium of claim 14, wherein the instructions further cause the one or more processors to: determine, using the neural network language model, a second probability of the non-terminal class given the one or more history candidate words, wherein the virtual FST is composed using the second probability of the non-terminal class given the one or more history candidate words.
 16. The non-transitory computer-readable medium of claim 14, wherein the instructions further cause the one or more processors to: traverse the user-specific language model FST, wherein a probability of the current candidate word among a plurality of candidate words represented in the user-specific language model FST is determined by traversing the user-specific language model FST, and wherein the virtual FST is composed using the probability of the current candidate word among the plurality of candidate words represented in the user-specific language model FST.
 17. The non-transitory computer-readable medium of claim 14, wherein the one or more virtual states of the virtual FST are composed using phone-word units from the WFST and based on the current candidate word represented in the user-specific language model FST.
 18. The non-transitory computer-readable medium of claim 14, wherein the instructions further cause the one or more processors to: prior to receiving the speech input: receive user-specific data; and generate the user-specific language model FST using the user-specific data.
 19. A method for performing speech-to-text conversion, the method comprising: at an electronic device having a processor and memory: receiving speech input; traversing, based on the speech input, a sequence of states and arcs of a weighted finite state transducer (WFST), wherein: the sequence of states and arcs represents one or more history candidate words and a current candidate word; and a first probability of the candidate word given the one or more history candidate words is determined by traversing the sequence of states and arcs of the WFST; traversing a negating finite state transducer (FST), wherein traversing the negating FST negates the first probability of the candidate word given the one or more history candidate words; composing a virtual FST using a neural network language model and based on the sequence of states and arcs of the WFST, wherein one or more virtual states of the virtual FST represent the current candidate word; traversing the one or more virtual states of the virtual FST, wherein a second probability of the candidate word given the one or more history candidate words is determined by traversing the one or more virtual states of the virtual FST; determining, based on the second probability of the candidate word given the one or more history candidate words, text corresponding to the speech input; based on the determined text, performing one or more tasks to obtain a result; and causing the result to be presented in spoken or visual form.
 20. An electronic device comprising: one or more processors; and memory having instructions stored thereon, the instructions, when executed by the one or more processors, cause the one or more processors to: receive speech input; traverse, based on the speech input, a sequence of states and arcs of a weighted finite state transducer (WFST), wherein: the sequence of states and arcs represents one or more history candidate words and a current candidate word; and a first probability of the candidate word given the one or more history candidate words is determined by traversing the sequence of states and arcs of the WFST; traverse a negating finite state transducer (FST), wherein traversing the negating FST negates the first probability of the candidate word given the one or more history candidate words; compose a virtual FST using a neural network language model and based on the sequence of states and arcs of the WFST, wherein one or more virtual states of the virtual FST represent the current candidate word; traverse the one or more virtual states of the virtual FST, wherein a second probability of the candidate word given the one or more history candidate words is determined by traversing the one or more virtual states of the virtual FST; determine, based on the second probability of the candidate word given the one or more history candidate words, text corresponding to the speech input; based on the determined text, perform one or more tasks to obtain a result; and cause the result to be presented in spoken or visual form.
 21. The method of claim 19, wherein the virtual FST is composed after traversing the sequence of states and arcs of the WFST.
 22. The method of claim 19, wherein only one arc transitions out of each virtual state of the one or more virtual states of the virtual FST.
 23. The method of claim 19, further comprising: composing the negating FST with the WFST prior to traversing the negating FST.
 24. The method of claim 19, wherein the WFST is a static finite state transducer built prior to receiving the speech input.
 25. The method of claim 19, wherein the WFST is a single finite state transducer composed from a Hidden Markov Model (HMM) topology, a context dependent phonetic model, a lexicon, and a language model.
 26. The electronic device of claim 20, wherein the virtual FST is composed after traversing the sequence of states and arcs of the WFST.
 27. The electronic device of claim 20, wherein only one arc transitions out of each virtual state of the one or more virtual states of the virtual FST.
 28. The electronic device of claim 20, wherein the one or more programs further include instructions that when executed by the one or more processors, cause the one or more processors to: compose the negating FST with the WFST prior to traversing the negating FST.
 29. The electronic device of claim 20, wherein the WFST is a static finite state transducer built prior to receiving the speech input.
 30. The electronic device of claim 20, wherein the WFST is a single finite state transducer composed from a Hidden Markov Model (HMM) topology, a context dependent phonetic model, a lexicon, and a language model.
 31. A method for performing speech-to-text conversion, the method comprising: at an electronic device having a processor and memory: receiving speech input; traversing, based on the speech input, a sequence of states and arcs of a weighted finite state transducer (WFST), wherein: the sequence of states and arcs represents one or more history candidate words and a non-terminal class; and a first probability of the non-terminal class given the one or more history candidate words is determined by traversing the sequence of states and arcs of the WFST; traversing a negating finite state transducer (FST), wherein traversing the negating FST negates the first probability of the non-terminal class given the one or more history candidate words; composing a virtual FST using a neural network language model and based on the sequence of states and arcs of the WFST, wherein one or more virtual states of the virtual FST represent a current candidate word corresponding to the non-terminal class; traversing the one or more virtual states of the virtual FST, wherein a probability of the current candidate word given the one or more history candidate words and the non-terminal class is determined by traversing the one or more virtual states of the virtual FST; determining, based on the probability of the candidate word given the one or more history candidate words and the non-terminal class, text corresponding to the speech input; based on the determined text, performing one or more tasks to obtain a result; and causing the result to be presented in spoken or visual form.
 32. The method of claim 31, further comprising: determining, using the neural network language model, a second probability of the non-terminal class given the one or more history candidate words, wherein the virtual FST is composed using the second probability of the non-terminal class given the one or more history candidate words.
 33. The method of claim 31, further comprising: traversing the user-specific language model FST, wherein a probability of the current candidate word among a plurality of candidate words represented in the user-specific language model FST is determined by traversing the user-specific language model FST, and wherein the virtual FST is composed using the probability of the current candidate word among the plurality of candidate words represented in the user-specific language model FST.
 34. The method of claim 31, wherein the one or more virtual states of the virtual FST are composed using phone-word units from the WFST and based on the current candidate word represented in the user-specific language model FST.
 35. The method of claim 31, further comprising: prior to receiving the speech input: receiving user-specific data; and generating the user-specific language model FST using the user-specific data.
 36. An electronic device comprising: one or more processors; and memory having instructions stored thereon, the instructions, when executed by the one or more processors, cause the one or more processors to: receive speech input; traverse, based on the speech input, a sequence of states and arcs of a weighted finite state transducer (WFST), wherein: the sequence of states and arcs represents one or more history candidate words and a non-terminal class; and a first probability of the non-terminal class given the one or more history candidate words is determined by traversing the sequence of states and arcs of the WFST; traverse a negating finite state transducer (FST), wherein traversing the negating FST negates the first probability of the non-terminal class given the one or more history candidate words; compose a virtual FST using a neural network language model and based on the sequence of states and arcs of the WFST, wherein one or more virtual states of the virtual FST represent a current candidate word corresponding to the non-terminal class; traverse the one or more virtual states of the virtual FST, wherein a probability of the current candidate word given the one or more history candidate words and the non-terminal class is determined by traversing the one or more virtual states of the virtual FST; determine, based on the probability of the current candidate word given the one or more history candidate words and the non-terminal class, text corresponding to the speech input; based on the determined text, perform one or more tasks to obtain a result; and cause the result to be presented in spoken or visual form.
 37. The electronic device of claim 36, wherein the one or more programs further include instructions that when executed by the one or more processors, cause the one or more processors to: determine, using the neural network language model, a second probability of the non-terminal class given the one or more history candidate words, wherein the virtual FST is composed using the second probability of the non-terminal class given the one or more history candidate words.
 38. The electronic device of claim 36, wherein the one or more programs further include instructions that when executed by the one or more processors, cause the one or more processors to: traverse the user-specific language model FST, wherein a probability of the current candidate word among a plurality of candidate words represented in the user-specific language model FST is determined by traversing the user-specific language model FST, and wherein the virtual FST is composed using the probability of the current candidate word among the plurality of candidate words represented in the user-specific language model FST.
 39. The electronic device of claim 36, wherein the one or more virtual states of the virtual FST are composed using phone-word units from the WFST and based on the current candidate word represented in the user-specific language model FST.
 40. The electronic device of claim 36, wherein the one or more programs further include instructions that when executed by the one or more processors, cause the one or more processors to: prior to receiving the speech input: receive user-specific data; and generate the user-specific language model FST using the user-specific data. 